diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 9d13d68..65c4042 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -26,12 +26,12 @@ jobs:
           settings: '${{ github.repository }}'
           target: ci/gem-test
 
-      - name: Install Ruby 3.3
+      - name: Install Ruby 4.0
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 3.3
+          ruby-version: 4.0
           bundler-cache: true
-          rubygems: '3.7.2'
+          rubygems: '4.0.11'
 
       - name: Switch to SSH remotes for the Git repository
         run: git-ssh-remotes
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 84cd2b9..fb969c9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,8 +18,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['3.3', '3.4', '4.0']
-        rails: ['8.0', '8.1']
+        ruby: ['4.0']
+        rails: ['8.1']
     env:
       BUNDLE_GEMFILE: 'gemfiles/rails_${{ matrix.rails }}.gemfile'
     steps:
@@ -36,7 +36,7 @@ jobs:
         with:
           ruby-version: ${{ matrix.ruby }}
           bundler-cache: true
-          rubygems: '3.7.2'
+          rubygems: '4.0.11'
 
       - name: Run the gem tests
         run: make test
diff --git a/.rubocop.yml b/.rubocop.yml
index 2a2be1c..108cb0d 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -17,8 +17,8 @@ AllCops:
   NewCops: enable
   SuggestExtensions: false
   DisplayCopNames: true
-  TargetRubyVersion: 3.3
-  TargetRailsVersion: 8.0
+  TargetRubyVersion: 4.0
+  TargetRailsVersion: 8.1
   Exclude:
     - bin/**/*
     - vendor/**/*
diff --git a/Appraisals b/Appraisals
index a0e9742..dc6a422 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,9 +1,5 @@
 # frozen_string_literal: true
 
-appraise 'rails-8.0' do
-  gem 'activesupport', '~> 8.0.0'
-end
-
 appraise 'rails-8.1' do
   gem 'activesupport', '~> 8.1.0'
 end
diff --git a/CHANGELOG.md b/CHANGELOG.md
index db0d242..8593bb9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 ### next
 
-* TODO: Replace this bullet point with an actual description of a change.
+* Dropped Ruby 3.x and Rails <8.1 support (#26)
 
 ### 2.9.0 (18 February 2026)
 
diff --git a/Dockerfile b/Dockerfile
index 5deb6c3..2079178 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,8 +1,8 @@
-FROM hausgold/ruby:3.3
+FROM hausgold/ruby:4.0
 LABEL org.opencontainers.image.authors="containers@hausgold.de"
 
 # Update system gem
-RUN gem update --system '3.7.2'
+RUN gem update --system '4.0.11'
 
 # Install system packages and the latest bundler
 RUN apt-get update -yqqq && \
@@ -11,7 +11,7 @@ RUN apt-get update -yqqq && \
     ca-certificates \
     bash-completion inotify-tools && \
   echo 'en_US.UTF-8 UTF-8' >> /etc/locale.gen && /usr/sbin/locale-gen && \
-  gem install bundler -v '~> 2.7.2' --no-document --no-prerelease
+  gem install bundler -v '~> 4.0.11' --no-document --no-prerelease
 
 # Add new web user
 RUN mkdir /app && \
diff --git a/Gemfile b/Gemfile
index 18b96ea..3d34ad6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem 'appraisal', '~> 2.4'
 gem 'bundler', '>= 2.6', '< 5'
 gem 'countless', '~> 2.2'
 gem 'guard-rspec', '~> 4.7'
-gem 'railties', '>= 8.0'
+gem 'railties', '>= 8.1'
 gem 'rake', '~> 13.0'
 gem 'rspec', '~> 3.12'
 gem 'rubocop'
diff --git a/Makefile b/Makefile
index ba1b9f0..5f86d20 100644
--- a/Makefile
+++ b/Makefile
@@ -118,7 +118,7 @@ test-style: \
 test-style-ruby:
 	# Run the static code analyzer (rubocop)
 	@$(call run-shell,$(BUNDLE) exec $(RUBOCOP) -a \
-		|| ($(TEST) $$($(RUBY_VERSION)) != '3.3' && true))
+		|| ($(TEST) $$($(RUBY_VERSION)) != '4.0' && true))
 
 clean:
 	# Clean the dependencies
diff --git a/gemfiles/rails_8.0.gemfile b/gemfiles/rails_8.0.gemfile
deleted file mode 100644
index e10df56..0000000
--- a/gemfiles/rails_8.0.gemfile
+++ /dev/null
@@ -1,23 +0,0 @@
-# This file was generated by Appraisal
-
-source "https://rubygems.org"
-
-gem "appraisal", "~> 2.4"
-gem "bundler", ">= 2.6", "< 5"
-gem "countless", "~> 2.2"
-gem "guard-rspec", "~> 4.7"
-gem "railties", ">= 8.0"
-gem "rake", "~> 13.0"
-gem "rspec", "~> 3.12"
-gem "rubocop"
-gem "rubocop-rails"
-gem "rubocop-rspec"
-gem "simplecov", ">= 0.22"
-gem "timecop", ">= 0.9.6"
-gem "vcr", "~> 6.0"
-gem "webmock", "~> 3.18"
-gem "yard", ">= 0.9.28"
-gem "yard-activesupport-concern", ">= 0.0.1"
-gem "activesupport", "~> 8.0.0"
-
-gemspec path: "../"
diff --git a/gemfiles/rails_8.1.gemfile b/gemfiles/rails_8.1.gemfile
index ff779e3..c2b31bb 100644
--- a/gemfiles/rails_8.1.gemfile
+++ b/gemfiles/rails_8.1.gemfile
@@ -6,7 +6,7 @@ gem "appraisal", "~> 2.4"
 gem "bundler", ">= 2.6", "< 5"
 gem "countless", "~> 2.2"
 gem "guard-rspec", "~> 4.7"
-gem "railties", ">= 8.0"
+gem "railties", ">= 8.1"
 gem "rake", "~> 13.0"
 gem "rspec", "~> 3.12"
 gem "rubocop"
diff --git a/keyless.gemspec b/keyless.gemspec
index 516c8d8..05931d5 100644
--- a/keyless.gemspec
+++ b/keyless.gemspec
@@ -33,9 +33,9 @@ Gem::Specification.new do |spec|
   spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = '>= 3.3'
+  spec.required_ruby_version = '>= 4.0'
 
-  spec.add_dependency 'activesupport', '>= 8.0'
+  spec.add_dependency 'activesupport', '>= 8.1'
   spec.add_dependency 'http', '~> 5.3'
   spec.add_dependency 'jwt', '>= 2.6'
   spec.add_dependency 'logger', '~> 1.7'
diff --git a/spec/fixtures/files/gen.rb b/spec/fixtures/files/gen.rb
index d474a8e..754e3af 100644
--- a/spec/fixtures/files/gen.rb
+++ b/spec/fixtures/files/gen.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require 'openssl'
-require 'pathname'
 
 root = Pathname.new(__dir__)