diff --git a/.github/workflows/precompile-gem.yml b/.github/workflows/precompile-gem.yml
index 5f60699..43637b5 100644
--- a/.github/workflows/precompile-gem.yml
+++ b/.github/workflows/precompile-gem.yml
@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.4.0-rc1"
+          ruby-version: "3.4"
           bundler-cache: true
       - run: bundle exec rake gem:${{ inputs.platform }}
       - uses: actions/upload-artifact@v4
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 54dec93..203d0b4 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -23,7 +23,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.4.0-rc1"
+          ruby-version: "3.4"
           bundler-cache: true
       - run: bundle exec rake gem
       - uses: actions/upload-artifact@v4
@@ -37,7 +37,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.4.0-rc1"
+          ruby-version: "3.4"
           bundler-cache: true
       - run: bundle exec rake java:gem
       - uses: actions/upload-artifact@v4
@@ -115,13 +115,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4.0-rc1", "truffleruby"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4", "truffleruby"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
           - { ruby: "3.1", rubygems: "default" }
           - { ruby: "3.2", rubygems: "default" }
           - { ruby: "3.3", rubygems: "default" }
-          - { ruby: "3.4.0-rc1", rubygems: "default" }
+          - { ruby: "3.4", rubygems: "default" }
           - { ruby: "truffleruby", rubygems: "default" }
     runs-on: "ubuntu-latest"
     steps:
@@ -144,13 +146,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4.0-rc1"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
           - { ruby: "3.1", rubygems: "default" }
           - { ruby: "3.2", rubygems: "default" }
           - { ruby: "3.3", rubygems: "default" }
-          - { ruby: "3.4.0-rc1", rubygems: "default" }
+          - { ruby: "3.4", rubygems: "default" }
     runs-on: "macos-13"
     steps:
       - uses: actions/checkout@v4
@@ -169,13 +173,21 @@ jobs:
 
   test-windows-2019:
     needs: "build-cruby-gem"
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["2.6", "2.7", "3.0"]
+        include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
+          - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: "windows-2019"
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.0"
-          rubygems: "3.5.23"
+          ruby-version: "${{ matrix.ruby }}"
+          rubygems: "${{ matrix.rubygems }}"
           bundler-cache: true
       - uses: actions/download-artifact@v4
         with:
@@ -234,8 +246,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     steps:
@@ -257,8 +271,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     steps:
@@ -280,8 +296,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     steps:
@@ -303,8 +321,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     steps:
@@ -326,8 +346,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     steps:
@@ -349,8 +371,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     steps:
@@ -372,13 +396,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4.0-rc1"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
           - { ruby: "3.1", rubygems: "default" }
           - { ruby: "3.2", rubygems: "default" }
           - { ruby: "3.3", rubygems: "default" }
-          - { ruby: "3.4.0-rc1", rubygems: "default" }
+          - { ruby: "3.4", rubygems: "default" }
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -400,8 +426,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4-rc"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: ubuntu-latest
     container:
@@ -419,13 +447,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4.0-rc1"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
           - { ruby: "3.1", rubygems: "default" }
           - { ruby: "3.2", rubygems: "default" }
           - { ruby: "3.3", rubygems: "default" }
-          - { ruby: "3.4.0-rc1", rubygems: "default" }
+          - { ruby: "3.4", rubygems: "default" }
     runs-on: macos-14
     steps:
       - uses: actions/checkout@v4
@@ -447,13 +477,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4.0-rc1"]
+        ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
         include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
           - { ruby: "3.0", rubygems: "3.5.23" }
           - { ruby: "3.1", rubygems: "default" }
           - { ruby: "3.2", rubygems: "default" }
           - { ruby: "3.3", rubygems: "default" }
-          - { ruby: "3.4.0-rc1", rubygems: "default" }
+          - { ruby: "3.4", rubygems: "default" }
     runs-on: macos-13
     steps:
       - uses: actions/checkout@v4
@@ -511,13 +543,21 @@ jobs:
 
   test-precompiled-x64-mingw32:
     needs: "precompile-x64-mingw32"
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["2.6", "2.7", "3.0"]
+        include:
+          - { ruby: "2.6", rubygems: "3.4.22" }
+          - { ruby: "2.7", rubygems: "3.4.22" }
+          - { ruby: "3.0", rubygems: "3.5.23" }
     runs-on: windows-2019
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.0"
-          rubygems: "3.5.23"
+          ruby-version: "${{ matrix.ruby }}"
+          rubygems: "${{ matrix.rubygems }}"
           bundler-cache: true
       - uses: actions/download-artifact@v4
         with:
@@ -536,7 +576,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby-pkgs@v1
         with:
-          ruby-version: "3.4.0-rc1"
+          ruby-version: "3.4"
           apt-get: valgrind
           bundler-cache: true
       - run: bundle exec rake test:valgrind
diff --git a/README.md b/README.md
index 4460a82..3c500c1 100644
--- a/README.md
+++ b/README.md
@@ -257,7 +257,7 @@ User.find_by(name: "alice")&.authenticate("password") #=> user
 
 This gem requires any of the following to run:
 
-* [Ruby](https://www.ruby-lang.org/en/) 3.0 to 3.4.0-rc1
+* [Ruby](https://www.ruby-lang.org/en/) 2.6 to 3.4
 * [JRuby](https://www.jruby.org) 9.4
 * [TruffleRuby](https://www.graalvm.org/ruby/) 24.1
 
diff --git a/Rakefile b/Rakefile
index 3736cb8..322f7c1 100644
--- a/Rakefile
+++ b/Rakefile
@@ -20,7 +20,7 @@ cross_platforms = %w[
   x86_64-linux-musl
 ].freeze
 
-ENV["RUBY_CC_VERSION"] = %w[3.4.0 3.3.5 3.2.0 3.1.0 3.0.0].join(":")
+ENV["RUBY_CC_VERSION"] = %w[3.4.0 3.3.5 3.2.0 3.1.0 3.0.0 2.7.0 2.6.0].join(":")
 
 gemspec = Gem::Specification.load("argon2id.gemspec")
 
diff --git a/argon2id.gemspec b/argon2id.gemspec
index 6c3c033..704a2b4 100644
--- a/argon2id.gemspec
+++ b/argon2id.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
     "source_code_uri" => "https://github.com/mudge/argon2id",
     "rubygems_mfa_required" => "true"
   }
-  s.required_ruby_version = ">= 3.0.0"
+  s.required_ruby_version = ">= 2.6.0"
   s.extensions = ["ext/argon2id/extconf.rb"]
   s.files = [
     "CHANGELOG.md",
@@ -54,6 +54,6 @@ Gem::Specification.new do |s|
   s.rdoc_options = ["--main", "README.md"]
 
   s.add_development_dependency("rake-compiler", "~> 1.2")
-  s.add_development_dependency("rake-compiler-dock", "~> 1.7.0.rc1")
+  s.add_development_dependency("rake-compiler-dock", "~> 1.7")
   s.add_development_dependency("minitest", "~> 5.25")
 end