diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 3236acc8b2..438d6c3ac1 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -24,17 +24,17 @@ jobs:
         config:
           - {os: windows-latest, r: '4.0',   vdiffr: true,  xref: true}
           - {os: macOS-latest,   r: '4.0',   vdiffr: true,  xref: true}
-          - {os: ubuntu-16.04,   r: 'devel', vdiffr: false, xref: true,  cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '4.0',   vdiffr: true,  xref: true,  cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.6',   vdiffr: false, xref: true,  cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.5',   vdiffr: false, xref: true,  cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.4',   vdiffr: false, xref: true,  cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.3',   vdiffr: false, xref: true,  cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
-          - {os: ubuntu-16.04,   r: '3.2',   vdiffr: false, xref: false, cran: "https://demo.rstudiopm.com/all/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: 'devel', vdiffr: false, xref: true,   rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest", http-user-agent: "R/4.0.0 (ubuntu-16.04) R (4.0.0 x86_64-pc-linux-gnu x86_64 linux-gnu) on GitHub Actions"}
+          - {os: ubuntu-16.04,   r: '4.0',   vdiffr: true,  xref: true,   rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: '3.6',   vdiffr: false, xref: true,   rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: '3.5',   vdiffr: false, xref: true,   rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: '3.4',   vdiffr: false, xref: true,   rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: '3.3',   vdiffr: false, xref: true,   rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: '3.2',   vdiffr: false, xref: false,  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
-      CRAN: ${{ matrix.config.cran }}
+      RSPM: ${{ matrix.config.rspm }}
       # don't treat missing suggested packages as error
       _R_CHECK_FORCE_SUGGESTS_: false
       # Some packages might unavailable on the older versions, so let's ignore xref warnings
@@ -49,6 +49,7 @@ jobs:
       - uses: r-lib/actions/setup-r@master
         with:
           r-version: ${{ matrix.config.r }}
+          http-user-agent: ${{ matrix.config.http-user-agent }}
 
       - uses: r-lib/actions/setup-pandoc@master
 
@@ -68,12 +69,11 @@ jobs:
 
       - name: Install system dependencies on Linux
         if: runner.os == 'Linux'
-        env:
-          RHUB_PLATFORM: linux-x86_64-ubuntu-gcc
         run: |
-          Rscript -e "remotes::install_github('r-hub/sysreqs')"
-          sysreqs=$(Rscript -e "cat(sysreqs::sysreq_commands('DESCRIPTION'))")
-          sudo -s eval "$sysreqs"
+          while read -r cmd
+          do
+            eval sudo $cmd
+          done < <(Rscript -e 'writeLines(remotes::system_requirements("ubuntu", "16.04"))')
 
       - name: Install system dependencies on macOS
         if: runner.os == 'macOS'
diff --git a/tests/testthat/helper-vdiffr.R b/tests/testthat/helper-vdiffr.R
index 77f38e3155..bf132c875e 100644
--- a/tests/testthat/helper-vdiffr.R
+++ b/tests/testthat/helper-vdiffr.R
@@ -2,4 +2,14 @@
 #   - VDIFFR_RUN_TESTS is "false" (on Travis CI with older versions and dev version of R)
 #   - CI is not set (on CRAN)
 
-expect_doppelganger <- vdiffr::expect_doppelganger
+if (requireNamespace("vdiffr", quietly = TRUE)) {
+  expect_doppelganger <- vdiffr::expect_doppelganger
+} else {
+  # If vdiffr is not available and visual tests are not explicitly disabled, raise error.
+  if (!identical(Sys.getenv("VDIFFR_RUN_TESTS"), "false")) {
+    abort("vdiffr is not installed")
+  }
+
+  # Otherwise, assign a dummy function
+  expect_doppelganger <- function(...) skip("vdiffr is not installed.")
+}
diff --git a/tests/testthat/test-ggsave.R b/tests/testthat/test-ggsave.R
index 4a4fbe0667..6d60439686 100644
--- a/tests/testthat/test-ggsave.R
+++ b/tests/testthat/test-ggsave.R
@@ -29,6 +29,10 @@ test_that("ggsave restores previous graphics device", {
 })
 
 test_that("ggsave uses theme background as image background", {
+  # FIXME: This should check svglite, but, at the time of writing this, there's already a binary
+  #        package of svglite, and it can be installed even if the dependency is not available, surprisingly...
+  skip_if_not_installed("systemfonts")
+
   path <- tempfile()
   on.exit(unlink(path))
   p <- ggplot(mtcars, aes(disp, mpg)) +