diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 21a833ebf..fb24aea83 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -291,7 +291,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ./
         with:
-          ruby-version: '2.2'
+          ruby-version: '2.3'
           bundler: 1.16.6
       - run: bundle --version | grep -F "1.16.6" # And not 1.17.x from ~> 1
 
@@ -369,7 +369,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        gemfile: [ rails5, rails6 ]
+        gemfile: [ rails7, rails8 ]
     name: "Test with ${{ matrix.gemfile }} gemfile"
     runs-on: ubuntu-latest
     env:
@@ -378,11 +378,9 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ./
         with:
-          ruby-version: '2.6'
+          ruby-version: '3.2'
           bundler-cache: true
       - run: bundle exec rails --version
-        env:
-          RUBYOPT: '-rlogger' # Rails 6 is missing a require 'logger' in active_support/logger_thread_safe_level.rb
 
   testTruffleRubyNokogiri:
     name: "Test installing a Gemfile with nokogiri on TruffleRuby"
diff --git a/README.md b/README.md
index b0eba4cb8..eddf0d67e 100644
--- a/README.md
+++ b/README.md
@@ -49,19 +49,21 @@ The action works on these [GitHub-hosted runners](https://docs.github.com/en/act
 
 | Operating System | Supported |
 | ---------------- | --------- |
-| Ubuntu  | `ubuntu-20.04`, `ubuntu-22.04`, `ubuntu-24.04`, `ubuntu-22.04-arm`, `ubuntu-24.04-arm` |
+| Ubuntu  | `ubuntu-22.04`, `ubuntu-24.04`, `ubuntu-22.04-arm`, `ubuntu-24.04-arm` |
 | macOS   | `macos-13` and newer versions |
 | Windows | `windows-2019`, `windows-2022` |
 
+Not all combinations of runner images and versions are supported.
+The list of available Ruby versions can be seen in [ruby-builder-versions.json](ruby-builder-versions.json) for Ubuntu and macOS
+(although some combinations are not available, see [the full list](https://github.com/ruby/ruby-builder/releases/tag/toolcache))
+and in [windows-versions.json](windows-versions.json) for Windows.
+
 The prebuilt releases are generated by [ruby-builder](https://github.com/ruby/ruby-builder)
 and on Windows by [RubyInstaller2](https://github.com/oneclick/rubyinstaller2).
 The `mingw`, `ucrt` and `mswin` builds are generated by [ruby-loco](https://github.com/MSP-Greg/ruby-loco).
 `ruby-head` is generated by [ruby-dev-builder](https://github.com/ruby/ruby-dev-builder),
 `jruby-head` is generated by [jruby-dev-builder](https://github.com/ruby/jruby-dev-builder),
 `truffleruby-head` and `truffleruby+graalvm-head` are generated by [truffleruby-dev-builder](https://github.com/ruby/truffleruby-dev-builder).
-The full list of available Ruby versions can be seen in [ruby-builder-versions.json](ruby-builder-versions.json) for Ubuntu and macOS
-(although some combinations are not available, see [the full list](https://github.com/ruby/ruby-builder/releases/tag/toolcache))
-and in [windows-versions.json](windows-versions.json) for Windows.
 
 ## Usage
 
diff --git a/common.js b/common.js
index e5730c1f6..12932cdd2 100644
--- a/common.js
+++ b/common.js
@@ -171,7 +171,6 @@ export async function hashFile(file) {
 
 // macos is not listed explicitly, see below
 const GitHubHostedPlatforms = [
-  'ubuntu-20.04-x64',
   'ubuntu-22.04-x64',
   'ubuntu-22.04-arm64',
   'ubuntu-24.04-x64',
diff --git a/dist/index.js b/dist/index.js
index da47e6da0..093b3ac3a 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -491,7 +491,6 @@ async function hashFile(file) {
 
 // macos is not listed explicitly, see below
 const GitHubHostedPlatforms = [
-  'ubuntu-20.04-x64',
   'ubuntu-22.04-x64',
   'ubuntu-22.04-arm64',
   'ubuntu-24.04-x64',
diff --git a/gemfiles/rails5.gemfile b/gemfiles/rails7.gemfile
similarity index 56%
rename from gemfiles/rails5.gemfile
rename to gemfiles/rails7.gemfile
index 199d28a21..73609d5b3 100644
--- a/gemfiles/rails5.gemfile
+++ b/gemfiles/rails7.gemfile
@@ -1,3 +1,3 @@
 source "https://rubygems.org"
 
-gem "rails", "~> 5.2.0"
+gem "rails", "~> 7.2.0"
diff --git a/gemfiles/rails6.gemfile b/gemfiles/rails8.gemfile
similarity index 56%
rename from gemfiles/rails6.gemfile
rename to gemfiles/rails8.gemfile
index b55405ccd..c6318c4f5 100644
--- a/gemfiles/rails6.gemfile
+++ b/gemfiles/rails8.gemfile
@@ -1,3 +1,3 @@
 source "https://rubygems.org"
 
-gem "rails", "~> 6.0.0"
+gem "rails", "~> 8.0.0"