diff --git a/.travis.yml b/.travis.yml
index 7b65eb2595..dda96b4065 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,13 @@ language: bash
 services: docker
 
 env:
+  - VERSION=7.3-rc VARIANT=stretch/cli
+  - VERSION=7.3-rc VARIANT=stretch/apache
+  - VERSION=7.3-rc VARIANT=stretch/fpm
+  - VERSION=7.3-rc VARIANT=stretch/zts
+  - VERSION=7.3-rc VARIANT=alpine3.8/cli
+  - VERSION=7.3-rc VARIANT=alpine3.8/fpm
+  - VERSION=7.3-rc VARIANT=alpine3.8/zts
   - VERSION=7.2 VARIANT=stretch/cli
   - VERSION=7.2 VARIANT=stretch/apache
   - VERSION=7.2 VARIANT=stretch/fpm
diff --git a/7.2/stretch/apache/Dockerfile b/7.2/stretch/apache/Dockerfile
index 53cff00a0a..c16110db8b 100644
--- a/7.2/stretch/apache/Dockerfile
+++ b/7.2/stretch/apache/Dockerfile
@@ -164,7 +164,6 @@ RUN set -eux; \
 	savedAptMark="$(apt-mark showmanual)"; \
 	apt-get update; \
 	apt-get install -y --no-install-recommends \
-		libargon2-0-dev \
 		libcurl4-openssl-dev \
 		libedit-dev \
 		libsodium-dev \
@@ -174,6 +173,20 @@ RUN set -eux; \
 		zlib1g-dev \
 		${PHP_EXTRA_BUILD_DEPS:-} \
 	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
 	rm -rf /var/lib/apt/lists/*; \
 	\
 	export \
diff --git a/7.2/stretch/cli/Dockerfile b/7.2/stretch/cli/Dockerfile
index 4e9d2ae321..4cf280079b 100644
--- a/7.2/stretch/cli/Dockerfile
+++ b/7.2/stretch/cli/Dockerfile
@@ -105,7 +105,6 @@ RUN set -eux; \
 	savedAptMark="$(apt-mark showmanual)"; \
 	apt-get update; \
 	apt-get install -y --no-install-recommends \
-		libargon2-0-dev \
 		libcurl4-openssl-dev \
 		libedit-dev \
 		libsodium-dev \
@@ -115,6 +114,20 @@ RUN set -eux; \
 		zlib1g-dev \
 		${PHP_EXTRA_BUILD_DEPS:-} \
 	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
 	rm -rf /var/lib/apt/lists/*; \
 	\
 	export \
diff --git a/7.2/stretch/fpm/Dockerfile b/7.2/stretch/fpm/Dockerfile
index efc940bc35..7695be083b 100644
--- a/7.2/stretch/fpm/Dockerfile
+++ b/7.2/stretch/fpm/Dockerfile
@@ -106,7 +106,6 @@ RUN set -eux; \
 	savedAptMark="$(apt-mark showmanual)"; \
 	apt-get update; \
 	apt-get install -y --no-install-recommends \
-		libargon2-0-dev \
 		libcurl4-openssl-dev \
 		libedit-dev \
 		libsodium-dev \
@@ -116,6 +115,20 @@ RUN set -eux; \
 		zlib1g-dev \
 		${PHP_EXTRA_BUILD_DEPS:-} \
 	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
 	rm -rf /var/lib/apt/lists/*; \
 	\
 	export \
diff --git a/7.2/stretch/zts/Dockerfile b/7.2/stretch/zts/Dockerfile
index d1a00a760f..4894835347 100644
--- a/7.2/stretch/zts/Dockerfile
+++ b/7.2/stretch/zts/Dockerfile
@@ -106,7 +106,6 @@ RUN set -eux; \
 	savedAptMark="$(apt-mark showmanual)"; \
 	apt-get update; \
 	apt-get install -y --no-install-recommends \
-		libargon2-0-dev \
 		libcurl4-openssl-dev \
 		libedit-dev \
 		libsodium-dev \
@@ -116,6 +115,20 @@ RUN set -eux; \
 		zlib1g-dev \
 		${PHP_EXTRA_BUILD_DEPS:-} \
 	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
 	rm -rf /var/lib/apt/lists/*; \
 	\
 	export \
diff --git a/7.3-rc/alpine3.8/cli/Dockerfile b/7.3-rc/alpine3.8/cli/Dockerfile
new file mode 100644
index 0000000000..f9e6b525a7
--- /dev/null
+++ b/7.3-rc/alpine3.8/cli/Dockerfile
@@ -0,0 +1,175 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM alpine:3.8
+
+# dependencies required for running "phpize"
+# these get automatically installed and removed by "docker-php-ext-*" (unless they're already installed)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev dpkg \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkgconf \
+		re2c
+
+# persistent / runtime deps
+RUN apk add --no-cache --virtual .persistent-deps \
+		ca-certificates \
+		curl \
+		tar \
+		xz \
+# https://github.com/docker-library/php/issues/494
+		libressl
+
+# ensure www-data user exists
+RUN set -x \
+	&& addgroup -g 82 -S www-data \
+	&& adduser -u 82 -D -S -G www-data www-data
+# 82 is the standard uid/gid for "www-data" in Alpine
+# http://git.alpinelinux.org/cgit/aports/tree/main/apache2/apache2.pre-install?h=v3.3.2
+# http://git.alpinelinux.org/cgit/aports/tree/main/lighttpd/lighttpd.pre-install?h=v3.3.2
+# http://git.alpinelinux.org/cgit/aports/tree/main/nginx-initscripts/nginx-initscripts.pre-install?h=v3.3.2
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	apk add --no-cache --virtual .fetch-deps \
+		gnupg \
+		wget \
+	; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apk del .fetch-deps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -xe \
+	&& apk add --no-cache --virtual .build-deps \
+		$PHPIZE_DEPS \
+		argon2-dev \
+		coreutils \
+		curl-dev \
+		libedit-dev \
+		libressl-dev \
+		libsodium-dev \
+		libxml2-dev \
+		sqlite-dev \
+	\
+	&& export CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	&& docker-php-source extract \
+	&& cd /usr/src/php \
+	&& gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" \
+	&& ./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		\
+		$PHP_EXTRA_CONFIGURE_ARGS \
+	&& make -j "$(nproc)" \
+	&& make install \
+	&& { find /usr/local/bin /usr/local/sbin -type f -perm +0111 -exec strip --strip-all '{}' + || true; } \
+	&& make clean \
+	&& cd / \
+	&& docker-php-source delete \
+	\
+	&& runDeps="$( \
+		scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
+			| tr ',' '\n' \
+			| sort -u \
+			| awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
+	)" \
+	&& apk add --no-cache --virtual .php-rundeps $runDeps \
+	\
+	&& apk del .build-deps \
+	\
+# https://github.com/docker-library/php/issues/443
+	&& pecl update-channels \
+	&& rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+CMD ["php", "-a"]
+##</autogenerated>##
diff --git a/7.3-rc/alpine3.8/cli/docker-php-entrypoint b/7.3-rc/alpine3.8/cli/docker-php-entrypoint
new file mode 100755
index 0000000000..88a016c16c
--- /dev/null
+++ b/7.3-rc/alpine3.8/cli/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- php "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/alpine3.8/cli/docker-php-ext-configure b/7.3-rc/alpine3.8/cli/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/alpine3.8/cli/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/alpine3.8/cli/docker-php-ext-enable b/7.3-rc/alpine3.8/cli/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/alpine3.8/cli/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/alpine3.8/cli/docker-php-ext-install b/7.3-rc/alpine3.8/cli/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/alpine3.8/cli/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/alpine3.8/cli/docker-php-source b/7.3-rc/alpine3.8/cli/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/alpine3.8/cli/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/7.3-rc/alpine3.8/fpm/Dockerfile b/7.3-rc/alpine3.8/fpm/Dockerfile
new file mode 100644
index 0000000000..cfdea0a503
--- /dev/null
+++ b/7.3-rc/alpine3.8/fpm/Dockerfile
@@ -0,0 +1,215 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM alpine:3.8
+
+# dependencies required for running "phpize"
+# these get automatically installed and removed by "docker-php-ext-*" (unless they're already installed)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev dpkg \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkgconf \
+		re2c
+
+# persistent / runtime deps
+RUN apk add --no-cache --virtual .persistent-deps \
+		ca-certificates \
+		curl \
+		tar \
+		xz \
+# https://github.com/docker-library/php/issues/494
+		libressl
+
+# ensure www-data user exists
+RUN set -x \
+	&& addgroup -g 82 -S www-data \
+	&& adduser -u 82 -D -S -G www-data www-data
+# 82 is the standard uid/gid for "www-data" in Alpine
+# http://git.alpinelinux.org/cgit/aports/tree/main/apache2/apache2.pre-install?h=v3.3.2
+# http://git.alpinelinux.org/cgit/aports/tree/main/lighttpd/lighttpd.pre-install?h=v3.3.2
+# http://git.alpinelinux.org/cgit/aports/tree/main/nginx-initscripts/nginx-initscripts.pre-install?h=v3.3.2
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+ENV PHP_EXTRA_CONFIGURE_ARGS --enable-fpm --with-fpm-user=www-data --with-fpm-group=www-data --disable-cgi
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	apk add --no-cache --virtual .fetch-deps \
+		gnupg \
+		wget \
+	; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apk del .fetch-deps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -xe \
+	&& apk add --no-cache --virtual .build-deps \
+		$PHPIZE_DEPS \
+		argon2-dev \
+		coreutils \
+		curl-dev \
+		libedit-dev \
+		libressl-dev \
+		libsodium-dev \
+		libxml2-dev \
+		sqlite-dev \
+	\
+	&& export CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	&& docker-php-source extract \
+	&& cd /usr/src/php \
+	&& gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" \
+	&& ./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		\
+		$PHP_EXTRA_CONFIGURE_ARGS \
+	&& make -j "$(nproc)" \
+	&& make install \
+	&& { find /usr/local/bin /usr/local/sbin -type f -perm +0111 -exec strip --strip-all '{}' + || true; } \
+	&& make clean \
+	&& cd / \
+	&& docker-php-source delete \
+	\
+	&& runDeps="$( \
+		scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
+			| tr ',' '\n' \
+			| sort -u \
+			| awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
+	)" \
+	&& apk add --no-cache --virtual .php-rundeps $runDeps \
+	\
+	&& apk del .build-deps \
+	\
+# https://github.com/docker-library/php/issues/443
+	&& pecl update-channels \
+	&& rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+WORKDIR /var/www/html
+
+RUN set -ex \
+	&& cd /usr/local/etc \
+	&& if [ -d php-fpm.d ]; then \
+		# for some reason, upstream's php-fpm.conf.default has "include=NONE/etc/php-fpm.d/*.conf"
+		sed 's!=NONE/!=!g' php-fpm.conf.default | tee php-fpm.conf > /dev/null; \
+		cp php-fpm.d/www.conf.default php-fpm.d/www.conf; \
+	else \
+		# PHP 5.x doesn't use "include=" by default, so we'll create our own simple config that mimics PHP 7+ for consistency
+		mkdir php-fpm.d; \
+		cp php-fpm.conf.default php-fpm.d/www.conf; \
+		{ \
+			echo '[global]'; \
+			echo 'include=etc/php-fpm.d/*.conf'; \
+		} | tee php-fpm.conf; \
+	fi \
+	&& { \
+		echo '[global]'; \
+		echo 'error_log = /proc/self/fd/2'; \
+		echo; \
+		echo '[www]'; \
+		echo '; if we send this to /proc/self/fd/1, it never appears'; \
+		echo 'access.log = /proc/self/fd/2'; \
+		echo; \
+		echo 'clear_env = no'; \
+		echo; \
+		echo '; Ensure worker stdout and stderr are sent to the main error log.'; \
+		echo 'catch_workers_output = yes'; \
+	} | tee php-fpm.d/docker.conf \
+	&& { \
+		echo '[global]'; \
+		echo 'daemonize = no'; \
+		echo; \
+		echo '[www]'; \
+		echo 'listen = 9000'; \
+	} | tee php-fpm.d/zz-docker.conf
+
+EXPOSE 9000
+CMD ["php-fpm"]
+##</autogenerated>##
diff --git a/7.3-rc/alpine3.8/fpm/docker-php-entrypoint b/7.3-rc/alpine3.8/fpm/docker-php-entrypoint
new file mode 100755
index 0000000000..86343d8038
--- /dev/null
+++ b/7.3-rc/alpine3.8/fpm/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- php-fpm "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/alpine3.8/fpm/docker-php-ext-configure b/7.3-rc/alpine3.8/fpm/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/alpine3.8/fpm/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/alpine3.8/fpm/docker-php-ext-enable b/7.3-rc/alpine3.8/fpm/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/alpine3.8/fpm/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/alpine3.8/fpm/docker-php-ext-install b/7.3-rc/alpine3.8/fpm/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/alpine3.8/fpm/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/alpine3.8/fpm/docker-php-source b/7.3-rc/alpine3.8/fpm/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/alpine3.8/fpm/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/7.3-rc/alpine3.8/zts/Dockerfile b/7.3-rc/alpine3.8/zts/Dockerfile
new file mode 100644
index 0000000000..4a594aa01b
--- /dev/null
+++ b/7.3-rc/alpine3.8/zts/Dockerfile
@@ -0,0 +1,176 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM alpine:3.8
+
+# dependencies required for running "phpize"
+# these get automatically installed and removed by "docker-php-ext-*" (unless they're already installed)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev dpkg \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkgconf \
+		re2c
+
+# persistent / runtime deps
+RUN apk add --no-cache --virtual .persistent-deps \
+		ca-certificates \
+		curl \
+		tar \
+		xz \
+# https://github.com/docker-library/php/issues/494
+		libressl
+
+# ensure www-data user exists
+RUN set -x \
+	&& addgroup -g 82 -S www-data \
+	&& adduser -u 82 -D -S -G www-data www-data
+# 82 is the standard uid/gid for "www-data" in Alpine
+# http://git.alpinelinux.org/cgit/aports/tree/main/apache2/apache2.pre-install?h=v3.3.2
+# http://git.alpinelinux.org/cgit/aports/tree/main/lighttpd/lighttpd.pre-install?h=v3.3.2
+# http://git.alpinelinux.org/cgit/aports/tree/main/nginx-initscripts/nginx-initscripts.pre-install?h=v3.3.2
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+ENV PHP_EXTRA_CONFIGURE_ARGS --enable-maintainer-zts --disable-cgi
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	apk add --no-cache --virtual .fetch-deps \
+		gnupg \
+		wget \
+	; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apk del .fetch-deps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -xe \
+	&& apk add --no-cache --virtual .build-deps \
+		$PHPIZE_DEPS \
+		argon2-dev \
+		coreutils \
+		curl-dev \
+		libedit-dev \
+		libressl-dev \
+		libsodium-dev \
+		libxml2-dev \
+		sqlite-dev \
+	\
+	&& export CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	&& docker-php-source extract \
+	&& cd /usr/src/php \
+	&& gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" \
+	&& ./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		\
+		$PHP_EXTRA_CONFIGURE_ARGS \
+	&& make -j "$(nproc)" \
+	&& make install \
+	&& { find /usr/local/bin /usr/local/sbin -type f -perm +0111 -exec strip --strip-all '{}' + || true; } \
+	&& make clean \
+	&& cd / \
+	&& docker-php-source delete \
+	\
+	&& runDeps="$( \
+		scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
+			| tr ',' '\n' \
+			| sort -u \
+			| awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
+	)" \
+	&& apk add --no-cache --virtual .php-rundeps $runDeps \
+	\
+	&& apk del .build-deps \
+	\
+# https://github.com/docker-library/php/issues/443
+	&& pecl update-channels \
+	&& rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+CMD ["php", "-a"]
+##</autogenerated>##
diff --git a/7.3-rc/alpine3.8/zts/docker-php-entrypoint b/7.3-rc/alpine3.8/zts/docker-php-entrypoint
new file mode 100755
index 0000000000..88a016c16c
--- /dev/null
+++ b/7.3-rc/alpine3.8/zts/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- php "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/alpine3.8/zts/docker-php-ext-configure b/7.3-rc/alpine3.8/zts/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/alpine3.8/zts/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/alpine3.8/zts/docker-php-ext-enable b/7.3-rc/alpine3.8/zts/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/alpine3.8/zts/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/alpine3.8/zts/docker-php-ext-install b/7.3-rc/alpine3.8/zts/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/alpine3.8/zts/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/alpine3.8/zts/docker-php-source b/7.3-rc/alpine3.8/zts/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/alpine3.8/zts/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/7.3-rc/stretch/apache/Dockerfile b/7.3-rc/stretch/apache/Dockerfile
new file mode 100644
index 0000000000..e0760db36f
--- /dev/null
+++ b/7.3-rc/stretch/apache/Dockerfile
@@ -0,0 +1,277 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM debian:stretch-slim
+
+# prevent Debian's PHP packages from being installed
+# https://github.com/docker-library/php/pull/542
+RUN set -eux; \
+	{ \
+		echo 'Package: php*'; \
+		echo 'Pin: release *'; \
+		echo 'Pin-Priority: -1'; \
+	} > /etc/apt/preferences.d/no-debian-php
+
+# dependencies required for running "phpize"
+# (see persistent deps below)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkg-config \
+		re2c
+
+# persistent / runtime deps
+RUN apt-get update && apt-get install -y \
+		$PHPIZE_DEPS \
+		ca-certificates \
+		curl \
+		xz-utils \
+	--no-install-recommends && rm -r /var/lib/apt/lists/*
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+RUN apt-get update \
+	&& apt-get install -y --no-install-recommends \
+		apache2 \
+	&& rm -rf /var/lib/apt/lists/*
+
+ENV APACHE_CONFDIR /etc/apache2
+ENV APACHE_ENVVARS $APACHE_CONFDIR/envvars
+
+RUN set -ex \
+	\
+# generically convert lines like
+#   export APACHE_RUN_USER=www-data
+# into
+#   : ${APACHE_RUN_USER:=www-data}
+#   export APACHE_RUN_USER
+# so that they can be overridden at runtime ("-e APACHE_RUN_USER=...")
+	&& sed -ri 's/^export ([^=]+)=(.*)$/: ${\1:=\2}\nexport \1/' "$APACHE_ENVVARS" \
+	\
+# setup directories and permissions
+	&& . "$APACHE_ENVVARS" \
+	&& for dir in \
+		"$APACHE_LOCK_DIR" \
+		"$APACHE_RUN_DIR" \
+		"$APACHE_LOG_DIR" \
+		/var/www/html \
+	; do \
+		rm -rvf "$dir" \
+		&& mkdir -p "$dir" \
+		&& chown -R "$APACHE_RUN_USER:$APACHE_RUN_GROUP" "$dir"; \
+	done
+
+# Apache + PHP requires preforking Apache for best results
+RUN a2dismod mpm_event && a2enmod mpm_prefork
+
+# logs should go to stdout / stderr
+RUN set -ex \
+	&& . "$APACHE_ENVVARS" \
+	&& ln -sfT /dev/stderr "$APACHE_LOG_DIR/error.log" \
+	&& ln -sfT /dev/stdout "$APACHE_LOG_DIR/access.log" \
+	&& ln -sfT /dev/stdout "$APACHE_LOG_DIR/other_vhosts_access.log"
+
+# PHP files should be handled by PHP, and should be preferred over any other file type
+RUN { \
+		echo '<FilesMatch \.php$>'; \
+		echo '\tSetHandler application/x-httpd-php'; \
+		echo '</FilesMatch>'; \
+		echo; \
+		echo 'DirectoryIndex disabled'; \
+		echo 'DirectoryIndex index.php index.html'; \
+		echo; \
+		echo '<Directory /var/www/>'; \
+		echo '\tOptions -Indexes'; \
+		echo '\tAllowOverride All'; \
+		echo '</Directory>'; \
+	} | tee "$APACHE_CONFDIR/conf-available/docker-php.conf" \
+	&& a2enconf docker-php
+
+ENV PHP_EXTRA_BUILD_DEPS apache2-dev
+ENV PHP_EXTRA_CONFIGURE_ARGS --with-apxs2 --disable-cgi
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	fetchDeps=' \
+		wget \
+	'; \
+	if ! command -v gpg > /dev/null; then \
+		fetchDeps="$fetchDeps \
+			dirmngr \
+			gnupg \
+		"; \
+	fi; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends $fetchDeps; \
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false $fetchDeps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -eux; \
+	\
+	savedAptMark="$(apt-mark showmanual)"; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends \
+		libcurl4-openssl-dev \
+		libedit-dev \
+		libsodium-dev \
+		libsqlite3-dev \
+		libssl-dev \
+		libxml2-dev \
+		zlib1g-dev \
+		${PHP_EXTRA_BUILD_DEPS:-} \
+	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	export \
+		CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	; \
+	docker-php-source extract; \
+	cd /usr/src/php; \
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
+	debMultiarch="$(dpkg-architecture --query DEB_BUILD_MULTIARCH)"; \
+# https://bugs.php.net/bug.php?id=74125
+	if [ ! -d /usr/include/curl ]; then \
+		ln -sT "/usr/include/$debMultiarch/curl" /usr/local/include/curl; \
+	fi; \
+	./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		--with-libdir="lib/$debMultiarch" \
+		\
+		${PHP_EXTRA_CONFIGURE_ARGS:-} \
+	; \
+	make -j "$(nproc)"; \
+	make install; \
+	find /usr/local/bin /usr/local/sbin -type f -executable -exec strip --strip-all '{}' + || true; \
+	make clean; \
+	cd /; \
+	docker-php-source delete; \
+	\
+# reset apt-mark's "manual" list so that "purge --auto-remove" will remove all build dependencies
+	apt-mark auto '.*' > /dev/null; \
+	[ -z "$savedAptMark" ] || apt-mark manual $savedAptMark; \
+	find /usr/local -type f -executable -exec ldd '{}' ';' \
+		| awk '/=>/ { print $(NF-1) }' \
+		| sort -u \
+		| xargs -r dpkg-query --search \
+		| cut -d: -f1 \
+		| sort -u \
+		| xargs -r apt-mark manual \
+	; \
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
+	\
+	php --version; \
+	\
+# https://github.com/docker-library/php/issues/443
+	pecl update-channels; \
+	rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+COPY apache2-foreground /usr/local/bin/
+WORKDIR /var/www/html
+
+EXPOSE 80
+CMD ["apache2-foreground"]
+##</autogenerated>##
diff --git a/7.3-rc/stretch/apache/apache2-foreground b/7.3-rc/stretch/apache/apache2-foreground
new file mode 100755
index 0000000000..5fe22e26f7
--- /dev/null
+++ b/7.3-rc/stretch/apache/apache2-foreground
@@ -0,0 +1,40 @@
+#!/bin/bash
+set -e
+
+# Note: we don't just use "apache2ctl" here because it itself is just a shell-script wrapper around apache2 which provides extra functionality like "apache2ctl start" for launching apache2 in the background.
+# (also, when run as "apache2ctl <apache args>", it does not use "exec", which leaves an undesirable resident shell process)
+
+: "${APACHE_CONFDIR:=/etc/apache2}"
+: "${APACHE_ENVVARS:=$APACHE_CONFDIR/envvars}"
+if test -f "$APACHE_ENVVARS"; then
+	. "$APACHE_ENVVARS"
+fi
+
+# Apache gets grumpy about PID files pre-existing
+: "${APACHE_RUN_DIR:=/var/run/apache2}"
+: "${APACHE_PID_FILE:=$APACHE_RUN_DIR/apache2.pid}"
+rm -f "$APACHE_PID_FILE"
+
+# create missing directories
+# (especially APACHE_RUN_DIR, APACHE_LOCK_DIR, and APACHE_LOG_DIR)
+for e in "${!APACHE_@}"; do
+	if [[ "$e" == *_DIR ]] && [[ "${!e}" == /* ]]; then
+		# handle "/var/lock" being a symlink to "/run/lock", but "/run/lock" not existing beforehand, so "/var/lock/something" fails to mkdir
+		#   mkdir: cannot create directory '/var/lock': File exists
+		dir="${!e}"
+		while [ "$dir" != "$(dirname "$dir")" ]; do
+			dir="$(dirname "$dir")"
+			if [ -d "$dir" ]; then
+				break
+			fi
+			absDir="$(readlink -f "$dir" 2>/dev/null || :)"
+			if [ -n "$absDir" ]; then
+				mkdir -p "$absDir"
+			fi
+		done
+
+		mkdir -p "${!e}"
+	fi
+done
+
+exec apache2 -DFOREGROUND "$@"
diff --git a/7.3-rc/stretch/apache/docker-php-entrypoint b/7.3-rc/stretch/apache/docker-php-entrypoint
new file mode 100755
index 0000000000..3d36d5e8cf
--- /dev/null
+++ b/7.3-rc/stretch/apache/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- apache2-foreground "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/stretch/apache/docker-php-ext-configure b/7.3-rc/stretch/apache/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/stretch/apache/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/stretch/apache/docker-php-ext-enable b/7.3-rc/stretch/apache/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/stretch/apache/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/stretch/apache/docker-php-ext-install b/7.3-rc/stretch/apache/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/stretch/apache/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/stretch/apache/docker-php-source b/7.3-rc/stretch/apache/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/stretch/apache/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/7.3-rc/stretch/cli/Dockerfile b/7.3-rc/stretch/cli/Dockerfile
new file mode 100644
index 0000000000..b154bf208a
--- /dev/null
+++ b/7.3-rc/stretch/cli/Dockerfile
@@ -0,0 +1,214 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM debian:stretch-slim
+
+# prevent Debian's PHP packages from being installed
+# https://github.com/docker-library/php/pull/542
+RUN set -eux; \
+	{ \
+		echo 'Package: php*'; \
+		echo 'Pin: release *'; \
+		echo 'Pin-Priority: -1'; \
+	} > /etc/apt/preferences.d/no-debian-php
+
+# dependencies required for running "phpize"
+# (see persistent deps below)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkg-config \
+		re2c
+
+# persistent / runtime deps
+RUN apt-get update && apt-get install -y \
+		$PHPIZE_DEPS \
+		ca-certificates \
+		curl \
+		xz-utils \
+	--no-install-recommends && rm -r /var/lib/apt/lists/*
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	fetchDeps=' \
+		wget \
+	'; \
+	if ! command -v gpg > /dev/null; then \
+		fetchDeps="$fetchDeps \
+			dirmngr \
+			gnupg \
+		"; \
+	fi; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends $fetchDeps; \
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false $fetchDeps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -eux; \
+	\
+	savedAptMark="$(apt-mark showmanual)"; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends \
+		libcurl4-openssl-dev \
+		libedit-dev \
+		libsodium-dev \
+		libsqlite3-dev \
+		libssl-dev \
+		libxml2-dev \
+		zlib1g-dev \
+		${PHP_EXTRA_BUILD_DEPS:-} \
+	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	export \
+		CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	; \
+	docker-php-source extract; \
+	cd /usr/src/php; \
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
+	debMultiarch="$(dpkg-architecture --query DEB_BUILD_MULTIARCH)"; \
+# https://bugs.php.net/bug.php?id=74125
+	if [ ! -d /usr/include/curl ]; then \
+		ln -sT "/usr/include/$debMultiarch/curl" /usr/local/include/curl; \
+	fi; \
+	./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		--with-libdir="lib/$debMultiarch" \
+		\
+		${PHP_EXTRA_CONFIGURE_ARGS:-} \
+	; \
+	make -j "$(nproc)"; \
+	make install; \
+	find /usr/local/bin /usr/local/sbin -type f -executable -exec strip --strip-all '{}' + || true; \
+	make clean; \
+	cd /; \
+	docker-php-source delete; \
+	\
+# reset apt-mark's "manual" list so that "purge --auto-remove" will remove all build dependencies
+	apt-mark auto '.*' > /dev/null; \
+	[ -z "$savedAptMark" ] || apt-mark manual $savedAptMark; \
+	find /usr/local -type f -executable -exec ldd '{}' ';' \
+		| awk '/=>/ { print $(NF-1) }' \
+		| sort -u \
+		| xargs -r dpkg-query --search \
+		| cut -d: -f1 \
+		| sort -u \
+		| xargs -r apt-mark manual \
+	; \
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
+	\
+	php --version; \
+	\
+# https://github.com/docker-library/php/issues/443
+	pecl update-channels; \
+	rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+CMD ["php", "-a"]
+##</autogenerated>##
diff --git a/7.3-rc/stretch/cli/docker-php-entrypoint b/7.3-rc/stretch/cli/docker-php-entrypoint
new file mode 100755
index 0000000000..88a016c16c
--- /dev/null
+++ b/7.3-rc/stretch/cli/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- php "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/stretch/cli/docker-php-ext-configure b/7.3-rc/stretch/cli/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/stretch/cli/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/stretch/cli/docker-php-ext-enable b/7.3-rc/stretch/cli/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/stretch/cli/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/stretch/cli/docker-php-ext-install b/7.3-rc/stretch/cli/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/stretch/cli/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/stretch/cli/docker-php-source b/7.3-rc/stretch/cli/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/stretch/cli/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/7.3-rc/stretch/fpm/Dockerfile b/7.3-rc/stretch/fpm/Dockerfile
new file mode 100644
index 0000000000..0ad9c152ea
--- /dev/null
+++ b/7.3-rc/stretch/fpm/Dockerfile
@@ -0,0 +1,254 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM debian:stretch-slim
+
+# prevent Debian's PHP packages from being installed
+# https://github.com/docker-library/php/pull/542
+RUN set -eux; \
+	{ \
+		echo 'Package: php*'; \
+		echo 'Pin: release *'; \
+		echo 'Pin-Priority: -1'; \
+	} > /etc/apt/preferences.d/no-debian-php
+
+# dependencies required for running "phpize"
+# (see persistent deps below)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkg-config \
+		re2c
+
+# persistent / runtime deps
+RUN apt-get update && apt-get install -y \
+		$PHPIZE_DEPS \
+		ca-certificates \
+		curl \
+		xz-utils \
+	--no-install-recommends && rm -r /var/lib/apt/lists/*
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+ENV PHP_EXTRA_CONFIGURE_ARGS --enable-fpm --with-fpm-user=www-data --with-fpm-group=www-data --disable-cgi
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	fetchDeps=' \
+		wget \
+	'; \
+	if ! command -v gpg > /dev/null; then \
+		fetchDeps="$fetchDeps \
+			dirmngr \
+			gnupg \
+		"; \
+	fi; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends $fetchDeps; \
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false $fetchDeps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -eux; \
+	\
+	savedAptMark="$(apt-mark showmanual)"; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends \
+		libcurl4-openssl-dev \
+		libedit-dev \
+		libsodium-dev \
+		libsqlite3-dev \
+		libssl-dev \
+		libxml2-dev \
+		zlib1g-dev \
+		${PHP_EXTRA_BUILD_DEPS:-} \
+	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	export \
+		CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	; \
+	docker-php-source extract; \
+	cd /usr/src/php; \
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
+	debMultiarch="$(dpkg-architecture --query DEB_BUILD_MULTIARCH)"; \
+# https://bugs.php.net/bug.php?id=74125
+	if [ ! -d /usr/include/curl ]; then \
+		ln -sT "/usr/include/$debMultiarch/curl" /usr/local/include/curl; \
+	fi; \
+	./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		--with-libdir="lib/$debMultiarch" \
+		\
+		${PHP_EXTRA_CONFIGURE_ARGS:-} \
+	; \
+	make -j "$(nproc)"; \
+	make install; \
+	find /usr/local/bin /usr/local/sbin -type f -executable -exec strip --strip-all '{}' + || true; \
+	make clean; \
+	cd /; \
+	docker-php-source delete; \
+	\
+# reset apt-mark's "manual" list so that "purge --auto-remove" will remove all build dependencies
+	apt-mark auto '.*' > /dev/null; \
+	[ -z "$savedAptMark" ] || apt-mark manual $savedAptMark; \
+	find /usr/local -type f -executable -exec ldd '{}' ';' \
+		| awk '/=>/ { print $(NF-1) }' \
+		| sort -u \
+		| xargs -r dpkg-query --search \
+		| cut -d: -f1 \
+		| sort -u \
+		| xargs -r apt-mark manual \
+	; \
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
+	\
+	php --version; \
+	\
+# https://github.com/docker-library/php/issues/443
+	pecl update-channels; \
+	rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+WORKDIR /var/www/html
+
+RUN set -ex \
+	&& cd /usr/local/etc \
+	&& if [ -d php-fpm.d ]; then \
+		# for some reason, upstream's php-fpm.conf.default has "include=NONE/etc/php-fpm.d/*.conf"
+		sed 's!=NONE/!=!g' php-fpm.conf.default | tee php-fpm.conf > /dev/null; \
+		cp php-fpm.d/www.conf.default php-fpm.d/www.conf; \
+	else \
+		# PHP 5.x doesn't use "include=" by default, so we'll create our own simple config that mimics PHP 7+ for consistency
+		mkdir php-fpm.d; \
+		cp php-fpm.conf.default php-fpm.d/www.conf; \
+		{ \
+			echo '[global]'; \
+			echo 'include=etc/php-fpm.d/*.conf'; \
+		} | tee php-fpm.conf; \
+	fi \
+	&& { \
+		echo '[global]'; \
+		echo 'error_log = /proc/self/fd/2'; \
+		echo; \
+		echo '[www]'; \
+		echo '; if we send this to /proc/self/fd/1, it never appears'; \
+		echo 'access.log = /proc/self/fd/2'; \
+		echo; \
+		echo 'clear_env = no'; \
+		echo; \
+		echo '; Ensure worker stdout and stderr are sent to the main error log.'; \
+		echo 'catch_workers_output = yes'; \
+	} | tee php-fpm.d/docker.conf \
+	&& { \
+		echo '[global]'; \
+		echo 'daemonize = no'; \
+		echo; \
+		echo '[www]'; \
+		echo 'listen = 9000'; \
+	} | tee php-fpm.d/zz-docker.conf
+
+EXPOSE 9000
+CMD ["php-fpm"]
+##</autogenerated>##
diff --git a/7.3-rc/stretch/fpm/docker-php-entrypoint b/7.3-rc/stretch/fpm/docker-php-entrypoint
new file mode 100755
index 0000000000..86343d8038
--- /dev/null
+++ b/7.3-rc/stretch/fpm/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- php-fpm "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/stretch/fpm/docker-php-ext-configure b/7.3-rc/stretch/fpm/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/stretch/fpm/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/stretch/fpm/docker-php-ext-enable b/7.3-rc/stretch/fpm/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/stretch/fpm/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/stretch/fpm/docker-php-ext-install b/7.3-rc/stretch/fpm/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/stretch/fpm/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/stretch/fpm/docker-php-source b/7.3-rc/stretch/fpm/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/stretch/fpm/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/7.3-rc/stretch/zts/Dockerfile b/7.3-rc/stretch/zts/Dockerfile
new file mode 100644
index 0000000000..85b3b1d6b4
--- /dev/null
+++ b/7.3-rc/stretch/zts/Dockerfile
@@ -0,0 +1,215 @@
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM debian:stretch-slim
+
+# prevent Debian's PHP packages from being installed
+# https://github.com/docker-library/php/pull/542
+RUN set -eux; \
+	{ \
+		echo 'Package: php*'; \
+		echo 'Pin: release *'; \
+		echo 'Pin-Priority: -1'; \
+	} > /etc/apt/preferences.d/no-debian-php
+
+# dependencies required for running "phpize"
+# (see persistent deps below)
+ENV PHPIZE_DEPS \
+		autoconf \
+		dpkg-dev \
+		file \
+		g++ \
+		gcc \
+		libc-dev \
+		make \
+		pkg-config \
+		re2c
+
+# persistent / runtime deps
+RUN apt-get update && apt-get install -y \
+		$PHPIZE_DEPS \
+		ca-certificates \
+		curl \
+		xz-utils \
+	--no-install-recommends && rm -r /var/lib/apt/lists/*
+
+ENV PHP_INI_DIR /usr/local/etc/php
+RUN mkdir -p $PHP_INI_DIR/conf.d
+
+##<autogenerated>##
+ENV PHP_EXTRA_CONFIGURE_ARGS --enable-maintainer-zts --disable-cgi
+##</autogenerated>##
+
+# Apply stack smash protection to functions using local buffers and alloca()
+# Make PHP's main executable position-independent (improves ASLR security mechanism, and has no performance impact on x86_64)
+# Enable optimization (-O2)
+# Enable linker optimization (this sorts the hash buckets to improve cache locality, and is non-default)
+# Adds GNU HASH segments to generated executables (this is used if present, and is much faster than sysv hash; in this configuration, sysv hash is also generated)
+# https://github.com/docker-library/php/issues/272
+ENV PHP_CFLAGS="-fstack-protector-strong -fpic -fpie -O2"
+ENV PHP_CPPFLAGS="$PHP_CFLAGS"
+ENV PHP_LDFLAGS="-Wl,-O1 -Wl,--hash-style=both -pie"
+
+ENV GPG_KEYS CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D
+
+ENV PHP_VERSION 7.3.0beta1
+ENV PHP_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz" PHP_ASC_URL="https://downloads.php.net/~cmb/php-7.3.0beta1.tar.xz.asc"
+ENV PHP_SHA256="6fc2bc65179f8228bfeab27ab01e558cfd5a1049c904243016c92414e254afcf" PHP_MD5=""
+
+RUN set -xe; \
+	\
+	fetchDeps=' \
+		wget \
+	'; \
+	if ! command -v gpg > /dev/null; then \
+		fetchDeps="$fetchDeps \
+			dirmngr \
+			gnupg \
+		"; \
+	fi; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends $fetchDeps; \
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	mkdir -p /usr/src; \
+	cd /usr/src; \
+	\
+	wget -O php.tar.xz "$PHP_URL"; \
+	\
+	if [ -n "$PHP_SHA256" ]; then \
+		echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; \
+	fi; \
+	if [ -n "$PHP_MD5" ]; then \
+		echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; \
+	fi; \
+	\
+	if [ -n "$PHP_ASC_URL" ]; then \
+		wget -O php.tar.xz.asc "$PHP_ASC_URL"; \
+		export GNUPGHOME="$(mktemp -d)"; \
+		for key in $GPG_KEYS; do \
+			gpg --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
+		done; \
+		gpg --batch --verify php.tar.xz.asc php.tar.xz; \
+		command -v gpgconf > /dev/null && gpgconf --kill all; \
+		rm -rf "$GNUPGHOME"; \
+	fi; \
+	\
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false $fetchDeps
+
+COPY docker-php-source /usr/local/bin/
+
+RUN set -eux; \
+	\
+	savedAptMark="$(apt-mark showmanual)"; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends \
+		libcurl4-openssl-dev \
+		libedit-dev \
+		libsodium-dev \
+		libsqlite3-dev \
+		libssl-dev \
+		libxml2-dev \
+		zlib1g-dev \
+		${PHP_EXTRA_BUILD_DEPS:-} \
+	; \
+##<argon2>##
+	sed -e 's/stretch/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
+	rm -rf /var/lib/apt/lists/*; \
+	\
+	export \
+		CFLAGS="$PHP_CFLAGS" \
+		CPPFLAGS="$PHP_CPPFLAGS" \
+		LDFLAGS="$PHP_LDFLAGS" \
+	; \
+	docker-php-source extract; \
+	cd /usr/src/php; \
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
+	debMultiarch="$(dpkg-architecture --query DEB_BUILD_MULTIARCH)"; \
+# https://bugs.php.net/bug.php?id=74125
+	if [ ! -d /usr/include/curl ]; then \
+		ln -sT "/usr/include/$debMultiarch/curl" /usr/local/include/curl; \
+	fi; \
+	./configure \
+		--build="$gnuArch" \
+		--with-config-file-path="$PHP_INI_DIR" \
+		--with-config-file-scan-dir="$PHP_INI_DIR/conf.d" \
+		\
+# make sure invalid --configure-flags are fatal errors intead of just warnings
+		--enable-option-checking=fatal \
+		\
+# https://github.com/docker-library/php/issues/439
+		--with-mhash \
+		\
+# --enable-ftp is included here because ftp_ssl_connect() needs ftp to be compiled statically (see https://github.com/docker-library/php/issues/236)
+		--enable-ftp \
+# --enable-mbstring is included here because otherwise there's no way to get pecl to use it properly (see https://github.com/docker-library/php/issues/195)
+		--enable-mbstring \
+# --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
+		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
+# https://wiki.php.net/rfc/libsodium
+		--with-sodium=shared \
+		\
+		--with-curl \
+		--with-libedit \
+		--with-openssl \
+		--with-zlib \
+		\
+# bundled pcre does not support JIT on s390x
+# https://manpages.debian.org/stretch/libpcre3-dev/pcrejit.3.en.html#AVAILABILITY_OF_JIT_SUPPORT
+		$(test "$gnuArch" = 's390x-linux-gnu' && echo '--without-pcre-jit') \
+		--with-libdir="lib/$debMultiarch" \
+		\
+		${PHP_EXTRA_CONFIGURE_ARGS:-} \
+	; \
+	make -j "$(nproc)"; \
+	make install; \
+	find /usr/local/bin /usr/local/sbin -type f -executable -exec strip --strip-all '{}' + || true; \
+	make clean; \
+	cd /; \
+	docker-php-source delete; \
+	\
+# reset apt-mark's "manual" list so that "purge --auto-remove" will remove all build dependencies
+	apt-mark auto '.*' > /dev/null; \
+	[ -z "$savedAptMark" ] || apt-mark manual $savedAptMark; \
+	find /usr/local -type f -executable -exec ldd '{}' ';' \
+		| awk '/=>/ { print $(NF-1) }' \
+		| sort -u \
+		| xargs -r dpkg-query --search \
+		| cut -d: -f1 \
+		| sort -u \
+		| xargs -r apt-mark manual \
+	; \
+	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
+	\
+	php --version; \
+	\
+# https://github.com/docker-library/php/issues/443
+	pecl update-channels; \
+	rm -rf /tmp/pear ~/.pearrc
+
+COPY docker-php-ext-* docker-php-entrypoint /usr/local/bin/
+
+# sodium was built as a shared module (so that it can be replaced later if so desired), so let's enable it too (https://github.com/docker-library/php/issues/598)
+RUN docker-php-ext-enable sodium
+
+ENTRYPOINT ["docker-php-entrypoint"]
+##<autogenerated>##
+CMD ["php", "-a"]
+##</autogenerated>##
diff --git a/7.3-rc/stretch/zts/docker-php-entrypoint b/7.3-rc/stretch/zts/docker-php-entrypoint
new file mode 100755
index 0000000000..88a016c16c
--- /dev/null
+++ b/7.3-rc/stretch/zts/docker-php-entrypoint
@@ -0,0 +1,9 @@
+#!/bin/sh
+set -e
+
+# first arg is `-f` or `--some-option`
+if [ "${1#-}" != "$1" ]; then
+	set -- php "$@"
+fi
+
+exec "$@"
diff --git a/7.3-rc/stretch/zts/docker-php-ext-configure b/7.3-rc/stretch/zts/docker-php-ext-configure
new file mode 100755
index 0000000000..9e949e1e13
--- /dev/null
+++ b/7.3-rc/stretch/zts/docker-php-ext-configure
@@ -0,0 +1,69 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 ext-name [configure flags]"
+	echo "   ie: $0 gd --with-jpeg-dir=/usr/local/something"
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+ext="$1"
+if [ -z "$ext" ] || [ ! -d "$ext" ]; then
+	usage >&2
+	exit 1
+fi
+shift
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual .phpize-deps-configure $PHPIZE_DEPS
+	fi
+fi
+
+if command -v dpkg-architecture > /dev/null; then
+	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"
+	set -- --build="$gnuArch" "$@"
+fi
+
+cd "$ext"
+phpize
+./configure "$@"
diff --git a/7.3-rc/stretch/zts/docker-php-ext-enable b/7.3-rc/stretch/zts/docker-php-ext-enable
new file mode 100755
index 0000000000..a2aa88ec5e
--- /dev/null
+++ b/7.3-rc/stretch/zts/docker-php-ext-enable
@@ -0,0 +1,114 @@
+#!/bin/sh
+set -e
+
+extDir="$(php -r 'echo ini_get("extension_dir");')"
+cd "$extDir"
+
+usage() {
+	echo "usage: $0 [options] module-name [module-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 --ini-name 0-apc.ini apcu apc"
+	echo
+	echo 'Possible values for module-name:'
+	find -maxdepth 1 \
+			-type f \
+			-name '*.so' \
+			-exec basename '{}' ';' \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?' --long 'help,ini-name:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+iniName=
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--ini-name) iniName="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+modules=
+for module; do
+	if [ -z "$module" ]; then
+		continue
+	fi
+	if [ -f "$module.so" ] && ! [ -f "$module" ]; then
+		# allow ".so" to be optional
+		module="$module.so"
+	fi
+	if ! [ -f "$module" ]; then
+		echo >&2 "error: '$module' does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	modules="$modules $module"
+done
+
+if [ -z "$modules" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if \
+		[ -n "$PHPIZE_DEPS" ] \
+		&& ! apk info --installed .phpize-deps > /dev/null \
+		&& ! apk info --installed .phpize-deps-configure > /dev/null \
+	; then
+		apk add --no-cache --virtual '.docker-php-ext-enable-deps' binutils
+		apkDel='.docker-php-ext-enable-deps'
+	fi
+fi
+
+for module in $modules; do
+	if readelf --wide --syms "$module" | grep -q ' zend_extension_entry$'; then
+		# https://wiki.php.net/internals/extensions#loading_zend_extensions
+		absModule="$(readlink -f "$module")"
+		line="zend_extension=$absModule"
+	else
+		line="extension=$module"
+	fi
+
+	ext="$(basename "$module")"
+	ext="${ext%.*}"
+	if php -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
+		# this isn't perfect, but it's better than nothing
+		# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
+		echo >&2
+		echo >&2 "warning: $ext ($module) is already loaded!"
+		echo >&2
+		continue
+	fi
+
+	ini="/usr/local/etc/php/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
+	if ! grep -q "$line" "$ini" 2>/dev/null; then
+		echo "$line" >> "$ini"
+	fi
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
diff --git a/7.3-rc/stretch/zts/docker-php-ext-install b/7.3-rc/stretch/zts/docker-php-ext-install
new file mode 100755
index 0000000000..d75d6d793b
--- /dev/null
+++ b/7.3-rc/stretch/zts/docker-php-ext-install
@@ -0,0 +1,122 @@
+#!/bin/sh
+set -e
+
+# prefer user supplied CFLAGS, but default to our PHP_CFLAGS
+: ${CFLAGS:=$PHP_CFLAGS}
+: ${CPPFLAGS:=$PHP_CPPFLAGS}
+: ${LDFLAGS:=$PHP_LDFLAGS}
+export CFLAGS CPPFLAGS LDFLAGS
+
+srcExists=
+if [ -d /usr/src/php ]; then
+	srcExists=1
+fi
+docker-php-source extract
+if [ -z "$srcExists" ]; then
+	touch /usr/src/php/.docker-delete-me
+fi
+
+cd /usr/src/php/ext
+
+usage() {
+	echo "usage: $0 [-jN] ext-name [ext-name ...]"
+	echo "   ie: $0 gd mysqli"
+	echo "       $0 pdo pdo_mysql"
+	echo "       $0 -j5 gd mbstring mysqli pdo pdo_mysql shmop"
+	echo
+	echo 'if custom ./configure arguments are necessary, see docker-php-ext-configure'
+	echo
+	echo 'Possible values for ext-name:'
+	find . \
+			-mindepth 2 \
+			-maxdepth 2 \
+			-type f \
+			-name 'config.m4' \
+		| xargs -n1 dirname \
+		| xargs -n1 basename \
+		| sort \
+		| xargs
+	echo
+	echo 'Some of the above modules are already compiled into PHP; please check'
+	echo 'the output of "php -i" to see which modules are already loaded.'
+}
+
+opts="$(getopt -o 'h?j:' --long 'help,jobs:' -- "$@" || { usage >&2 && false; })"
+eval set -- "$opts"
+
+j=1
+while true; do
+	flag="$1"
+	shift
+	case "$flag" in
+		--help|-h|'-?') usage && exit 0 ;;
+		--jobs|-j) j="$1" && shift ;;
+		--) break ;;
+		*)
+			{
+				echo "error: unknown flag: $flag"
+				usage
+			} >&2
+			exit 1
+			;;
+	esac
+done
+
+exts=
+for ext; do
+	if [ -z "$ext" ]; then
+		continue
+	fi
+	if [ ! -d "$ext" ]; then
+		echo >&2 "error: $PWD/$ext does not exist"
+		echo >&2
+		usage >&2
+		exit 1
+	fi
+	exts="$exts $ext"
+done
+
+if [ -z "$exts" ]; then
+	usage >&2
+	exit 1
+fi
+
+pm='unknown'
+if [ -e /lib/apk/db/installed ]; then
+	pm='apk'
+fi
+
+apkDel=
+if [ "$pm" = 'apk' ]; then
+	if [ -n "$PHPIZE_DEPS" ]; then
+		if apk info --installed .phpize-deps-configure > /dev/null; then
+			apkDel='.phpize-deps-configure'
+		elif ! apk info --installed .phpize-deps > /dev/null; then
+			apk add --no-cache --virtual .phpize-deps $PHPIZE_DEPS
+			apkDel='.phpize-deps'
+		fi
+	fi
+fi
+
+popDir="$PWD"
+for ext in $exts; do
+	cd "$ext"
+	[ -e Makefile ] || docker-php-ext-configure "$ext"
+	make -j"$j"
+	make -j"$j" install
+	find modules \
+		-maxdepth 1 \
+		-name '*.so' \
+		-exec basename '{}' ';' \
+			| xargs -r docker-php-ext-enable
+	make -j"$j" clean
+	cd "$popDir"
+done
+
+if [ "$pm" = 'apk' ] && [ -n "$apkDel" ]; then
+	apk del $apkDel
+fi
+
+if [ -e /usr/src/php/.docker-delete-me ]; then
+	docker-php-source delete
+fi
diff --git a/7.3-rc/stretch/zts/docker-php-source b/7.3-rc/stretch/zts/docker-php-source
new file mode 100755
index 0000000000..9033d243de
--- /dev/null
+++ b/7.3-rc/stretch/zts/docker-php-source
@@ -0,0 +1,34 @@
+#!/bin/sh
+set -e
+
+dir=/usr/src/php
+
+usage() {
+	echo "usage: $0 COMMAND"
+	echo
+	echo "Manage php source tarball lifecycle."
+	echo
+	echo "Commands:"
+	echo "   extract  extract php source tarball into directory $dir if not already done."
+	echo "   delete   delete extracted php source located into $dir if not already done."
+	echo
+}
+
+case "$1" in
+	extract)
+		mkdir -p "$dir"
+		if [ ! -f "$dir/.docker-extracted" ]; then
+			tar -Jxf /usr/src/php.tar.xz -C "$dir" --strip-components=1
+			touch "$dir/.docker-extracted"
+		fi
+		;;
+
+	delete)
+		rm -rf "$dir"
+		;;
+
+	*)
+		usage
+		exit 1
+		;;
+esac
diff --git a/Dockerfile-alpine.template b/Dockerfile-alpine.template
index 9d665c5a0d..ffa2dd2ddc 100644
--- a/Dockerfile-alpine.template
+++ b/Dockerfile-alpine.template
@@ -90,6 +90,7 @@ COPY docker-php-source /usr/local/bin/
 RUN set -xe \
 	&& apk add --no-cache --virtual .build-deps \
 		$PHPIZE_DEPS \
+		argon2-dev \
 		coreutils \
 		curl-dev \
 		libedit-dev \
@@ -121,6 +122,8 @@ RUN set -xe \
 		--enable-mbstring \
 # --enable-mysqlnd is included here because it's harder to compile after the fact than extensions are (since it's a plugin for several extensions, not an extension in itself)
 		--enable-mysqlnd \
+# https://wiki.php.net/rfc/argon2_password_hash (7.2+)
+		--with-password-argon2 \
 # https://wiki.php.net/rfc/libsodium
 		--with-sodium=shared \
 		\
diff --git a/Dockerfile-debian.template b/Dockerfile-debian.template
index 09aa17aa32..5b3f1ab661 100644
--- a/Dockerfile-debian.template
+++ b/Dockerfile-debian.template
@@ -1,4 +1,4 @@
-FROM debian:%%DEBIAN_SUITE%%
+FROM debian:%%DEBIAN_TAG%%
 
 # prevent Debian's PHP packages from being installed
 # https://github.com/docker-library/php/pull/542
@@ -99,7 +99,6 @@ RUN set -eux; \
 	savedAptMark="$(apt-mark showmanual)"; \
 	apt-get update; \
 	apt-get install -y --no-install-recommends \
-		libargon2-0-dev \
 		libcurl4-openssl-dev \
 		libedit-dev \
 		libsodium-dev \
@@ -109,6 +108,20 @@ RUN set -eux; \
 		zlib1g-dev \
 		${PHP_EXTRA_BUILD_DEPS:-} \
 	; \
+##<argon2>##
+	sed -e 's/%%DEBIAN_SUITE%%/buster/g' /etc/apt/sources.list > /etc/apt/sources.list.d/buster.list; \
+	{ \
+		echo 'Package: *'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: -10'; \
+		echo; \
+		echo 'Package: libargon2*'; \
+		echo 'Pin: release n=buster'; \
+		echo 'Pin-Priority: 990'; \
+	} > /etc/apt/preferences.d/argon2-buster; \
+	apt-get update; \
+	apt-get install -y --no-install-recommends libargon2-dev; \
+##</argon2>##
 	rm -rf /var/lib/apt/lists/*; \
 	\
 	export \
diff --git a/generate-stackbrew-library.sh b/generate-stackbrew-library.sh
index c67e0cf7d5..71c43a0576 100755
--- a/generate-stackbrew-library.sh
+++ b/generate-stackbrew-library.sh
@@ -8,7 +8,7 @@ declare -A aliases=(
 )
 
 defaultDebianSuite='stretch'
-defaultAlpineVersion='3.7'
+defaultAlpineVersion='3.8'
 
 self="$(basename "$BASH_SOURCE")"
 cd "$(dirname "$(readlink -f "$BASH_SOURCE")")"
@@ -83,7 +83,7 @@ for version in "${versions[@]}"; do
 	for suite in \
 		stretch \
 		jessie \
-		alpine{3.7,3.6} \
+		alpine{3.8,3.7,3.6} \
 	; do
 		for variant in \
 			cli \
diff --git a/update.sh b/update.sh
index 5a608bc6ec..fbf60def9f 100755
--- a/update.sh
+++ b/update.sh
@@ -3,6 +3,11 @@ set -e
 
 # https://secure.php.net/gpg-keys.php
 declare -A gpgKeys=(
+	# https://wiki.php.net/todo/php73
+	# cmb & stas
+	# https://secure.php.net/gpg-keys.php#gpg-7.3
+	[7.3]='CBAF69F173A0FEA4B537F470D66C9593118BCCB6 F38252826ACD957EF380D39F2F7956BC5DA04B5D'
+
 	# https://wiki.php.net/todo/php72
 	# pollita & remi
 	# https://secure.php.net/downloads.php#gpg-7.2
@@ -125,7 +130,7 @@ for version in "${versions[@]}"; do
 
 	dockerfiles=()
 
-	for suite in stretch jessie alpine{3.7,3.6}; do
+	for suite in stretch jessie alpine{3.8,3.7,3.6}; do
 		[ -d "$version/$suite" ] || continue
 		alpineVer="${suite#alpine}"
 
@@ -155,10 +160,12 @@ for version in "${versions[@]}"; do
 			if [ "$variant" = 'apache' ]; then
 				cp -a apache2-foreground "$version/$suite/$variant/"
 			fi
-			if [ "$majorVersion" = '5' ] || [ "$majorVersion" = '7' -a "$minorVersion" -lt '2' ] || [ "$suite" = 'jessie' ]; then
-				# argon2 password hashing is only supported in 7.2+ and stretch+
-				sed -ri '/argon2/d' "$version/$suite/$variant/Dockerfile"
-				# Alpine 3.7+ _should_ include an "argon2-dev" package, but we should cross that bridge when we come to it
+			if [ "$majorVersion" = '5' ] || [ "$majorVersion" = '7' -a "$minorVersion" -lt '2' ] || [ "$suite" = 'jessie' ] || [ "$suite" = 'alpine3.6' ] || [ "$suite" = 'alpine3.7' ]; then
+				# argon2 password hashing is only supported in 7.2+ and stretch+ / alpine 3.8+
+				sed -ri \
+					-e '/##<argon2>##/,/##<\/argon2>##/d' \
+					-e '/argon2/d' \
+					"$version/$suite/$variant/Dockerfile"
 			fi
 			if [ "$majorVersion" = '5' ] || [ "$majorVersion" = '7' -a "$minorVersion" -lt '2' ]; then
 				# sodium is part of php core 7.2+ https://wiki.php.net/rfc/libsodium
@@ -180,7 +187,8 @@ for version in "${versions[@]}"; do
 			# automatic `-slim` for stretch
 			# TODO always add slim once jessie is removed
 			sed -ri \
-				-e 's!%%DEBIAN_SUITE%%!'"${suite/stretch/stretch-slim}"'!' \
+				-e 's!%%DEBIAN_TAG%%!'"${suite/stretch/stretch-slim}"'!' \
+				-e 's!%%DEBIAN_SUITE%%!'"$suite"'!' \
 				-e 's!%%ALPINE_VERSION%%!'"$alpineVer"'!' \
 				"$version/$suite/$variant/Dockerfile"
 			dockerfiles+=( "$version/$suite/$variant/Dockerfile" )