diff --git a/snooty.toml b/snooty.toml
index a15ae3ae..de53fb1e 100644
--- a/snooty.toml
+++ b/snooty.toml
@@ -40,7 +40,7 @@ php-library = "MongoDB PHP Library"
 
 [constants]
 php-library = "MongoDB PHP Library"
-version = "1.20"
+version = "1.21"
 source-gh-branch = "v1.x"
 full-version = "{+version+}.0"
 extension-short = "PHP extension"
@@ -52,3 +52,4 @@ api = "https://www.mongodb.com/docs/php-library/current/reference"
 string-data-type = "``string``"
 bool-data-type = "``bool``"
 int-data-type = "``int``"
+language = "PHP"
\ No newline at end of file
diff --git a/source/upgrade.txt b/source/upgrade.txt
index 2ea4cedf..a9171431 100644
--- a/source/upgrade.txt
+++ b/source/upgrade.txt
@@ -29,15 +29,16 @@ How to Upgrade
 
 Before you upgrade, perform the following actions:
 
-- Ensure the new {+library-short+} version is compatible with the {+mdb-server+} versions
-  your application connects to and the PHP version your
-  application compiles with. For version compatibility information, see the
-  :ref:`{+php-library+} Compatibility <php-compatibility>`
-  page.
 - Address any breaking changes between the library version
   your application is using and your planned upgrade version in the
   :ref:`Breaking Changes <php-breaking-changes>` section.
 
+- Ensure the new {+library-short+} version is compatible with the {+mdb-server+} versions
+  your application connects to and the PHP version your
+  application compiles with. For version compatibility information, see the
+  :ref:`Compatibility Changes <php-compat-changes>` section and the 
+  :ref:`{+php-library+} Compatibility <php-compatibility>` page.
+
 .. tip::
 
    To ensure compatibility across {+mdb-server+} versions when
@@ -78,22 +79,38 @@ A breaking change is a change of a convention or a behavior starting in a specif
 version of the library. This type of change may prevent your application from working
 properly if not addressed before upgrading the library.
 
-The breaking changes in this section are categorized by the library version that introduced
-them. When upgrading library versions, address all the breaking changes between the current
-and upgrade versions.
+The breaking changes in this section are categorized by the library
+version that introduced them. Only major library versions introduce
+breaking changes. When upgrading versions, address all
+the breaking changes between the current and upgrade versions.
 
 For more information on release changes, see the release notes and associated 
 JIRA tickets for each release on `GitHub <https://github.com/mongodb/mongo-php-library/releases>`__.
 
-Version 1.20 Breaking Changes
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Version 1.0 Breaking Changes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To view breaking changes for this major release, see the 
+:github:`release notes </mongodb/mongo-php-library/releases/tag/1.0.0>`
+on GitHub.
+
+.. _php-compat-changes:
+
+Compatibility Changes
+---------------------
+
+This section describes the {+mdb-server+} and {+language+} compatibility
+changes introduced in {+php-library+} version releases.
+
+Version 1.x Compatibility Changes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-This library version introduces the following breaking changes:
+This library version introduces the following compatibility changes:
 
-- Drops support for {+mdb-server+} 3.6.
+- Drops support for {+mdb-server+} 3.6 in {+php-library+} v1.20
 
-Version 1.19 and Earlier
-~~~~~~~~~~~~~~~~~~~~~~~~
+.. tip:: Earlier Library Versions
 
-For library versions 1.19 and earlier, see the release notes and associated 
-JIRA tickets for each release on `GitHub <https://github.com/mongodb/mongo-php-library/releases>`__.  
+   To view compatibility changes for {+php-library+} versions 1.19 and earlier, see the
+   release notes and associated JIRA tickets for each release on `GitHub
+   <https://github.com/mongodb/mongo-php-library/releases>`__.