diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 82c49b3..e940a81 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -23,6 +23,8 @@ jobs:
           - '3.0'
           - 3.1
           - 3.2
+          - 3.3
+          - 3.4.0-preview1
           - head
           - jruby
           - jruby-head
@@ -34,8 +36,14 @@ jobs:
           - { os: ubuntu,  ruby: 2.2 }
           - { os: ubuntu,  ruby: mingw }
           - { os: macos,   ruby: mingw }
+          - { os: macos,   ruby: 2.1 }
+          - { os: macos,   ruby: 2.2 }
+          - { os: macos,   ruby: 2.3 }
+          - { os: macos,   ruby: 2.4 }
+          - { os: macos,   ruby: 2.5 }
           - { os: windows, ruby: truffleruby }
           - { os: windows, ruby: truffleruby-head }
+          - { os: windows, ruby: 3.4.0-preview1 }
 
     runs-on: ${{ matrix.os }}-latest
 
@@ -57,11 +65,17 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        os:
+          - ubuntu-20.04
+          - macos-13
         ruby:
           - 2.1
           - 2.2
+          - 2.3
+          - 2.4
+          - 2.5
 
-    runs-on: ubuntu-20.04
+    runs-on: ${{ matrix.os }}
 
     steps:
       - uses: actions/checkout@v2
diff --git a/README.md b/README.md
index dd55971..88598ad 100644
--- a/README.md
+++ b/README.md
@@ -30,8 +30,8 @@ re-hash those passwords. This vulnerability only affected the JRuby gem.
 The bcrypt gem is available on the following Ruby platforms:
 
 * JRuby
-* RubyInstaller 2.0 – 3.0 builds on Windows with the DevKit
-* Any 2.0 – 3.0 Ruby on a BSD/OS X/Linux system with a compiler
+* RubyInstaller builds on Windows with the DevKit
+* Any modern Ruby on a BSD/OS X/Linux system with a compiler
 
 ## How to use `bcrypt()` in your Rails application