diff --git a/.github/workflows/rubocop.yml b/.github/workflows/rubocop.yml
index 9c44d9a..e82d395 100644
--- a/.github/workflows/rubocop.yml
+++ b/.github/workflows/rubocop.yml
@@ -2,9 +2,9 @@ name: RuboCop
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
 
 permissions:
   contents: read
@@ -19,15 +19,15 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ruby-version: ['3.3']
+        ruby-version: ["3.1"]
 
     steps:
-    - uses: actions/checkout@v4
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
-      with:
-        ruby-version: ${{ matrix.ruby-version }}
-        bundler-cache: true
-        rubygems: latest
-    - name: Ruby linter
-      run: bundle exec bin/rubocop
+      - uses: actions/checkout@v4
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+          rubygems: latest
+      - name: Ruby linter
+        run: bundle exec bin/rubocop
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 48adea8..0e3494d 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,9 +2,9 @@ name: Test
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
 
 permissions:
   contents: read
@@ -15,22 +15,22 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.0', '3.1', '3.2', '3.3']
-        channel: ['stable']
+        ruby-version: ["3.1", "3.2", "3.3"]
+        channel: ["stable"]
 
         include:
-          - ruby-version: 'head'
-            channel: 'experimental'
+          - ruby-version: "head"
+            channel: "experimental"
 
     continue-on-error: ${{ matrix.channel != 'stable' }}
 
     steps:
-    - uses: actions/checkout@v4
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
-      with:
-        ruby-version: ${{ matrix.ruby-version }}
-        bundler-cache: true
-        rubygems: latest
-    - name: Run specs
-      run: bundle exec rake
+      - uses: actions/checkout@v4
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+          rubygems: latest
+      - name: Run specs
+        run: bundle exec rake
diff --git a/.rubocop.yml b/.rubocop.yml
index 533c61c..5b7d757 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -6,12 +6,16 @@ require:
 
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 3.0
+  TargetRubyVersion: 3.1
   DisplayStyleGuide: true
   ExtraDetails: true
   Exclude:
-    - 'bin/**/*'
-    - 'vendor/bundle/**/*'
+    - .git/**/*
+    - .github/**/*
+    - bin/**/*
+    - coverage/**/*
+    - doc/**/*
+    - vendor/**/*
 
 RSpec/ExampleLength:
   Max: 10
diff --git a/.ruby-version b/.ruby-version
index a0891f5..9c25013 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.3.4
+3.3.6
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 62e0b12..c49e4cc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Pundit Matchers
 
+# 4.0.0 (2024-12-18)
+
+- Drop Ruby < 3.1 compatibility. Please upgrade your Rails application to use
+  Ruby 3.1 or higher.
+
 ## 3.1.2 (2023-06-28)
 
 - Fix namespace resolution under some circumstances
diff --git a/Dockerfile b/Dockerfile
index 9b66785..6c86d5c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:3.1.2
+FROM ruby:3.3.6
 
 LABEL maintainer="chris@chrisalley.info"
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 460345d..d77d38c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    pundit-matchers (3.1.2)
+    pundit-matchers (4.0.0)
       rspec-core (~> 3.12)
       rspec-expectations (~> 3.12)
       rspec-mocks (~> 3.12)
diff --git a/README.md b/README.md
index 285ddd3..7d3bdbc 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ group:
 
 ```ruby
 group :test do
-  gem 'pundit-matchers', '~> 3.1'
+  gem 'pundit-matchers', '~> 4.0'
 end
 ```
 
@@ -26,7 +26,7 @@ And then execute the following command:
 Pundit Matchers expects that the application you're testing is using a
 software stack consisting of:
 
-- Ruby 3+
+- Ruby 3.1+
 - Pundit 2+
 - RSpec 3.12+
 
diff --git a/pundit-matchers.gemspec b/pundit-matchers.gemspec
index 16681d5..3bce5ad 100644
--- a/pundit-matchers.gemspec
+++ b/pundit-matchers.gemspec
@@ -2,7 +2,7 @@
 
 Gem::Specification.new do |s|
   s.name        = 'pundit-matchers'
-  s.version     = '3.1.2'
+  s.version     = '4.0.0'
   s.summary     = 'RSpec matchers for Pundit policies'
   s.description = 'A set of RSpec matchers for testing Pundit authorisation ' \
                   'policies'
@@ -13,7 +13,7 @@ Gem::Specification.new do |s|
   s.homepage    = 'https://github.com/pundit-community/pundit-matchers'
   s.license     = 'MIT'
   s.metadata['rubygems_mfa_required'] = 'true'
-  s.required_ruby_version = '>= 3.0'
+  s.required_ruby_version = '>= 3.1'
 
   %w[core expectations mocks support].each do |name|
     s.add_dependency "rspec-#{name}", '~> 3.12'
diff --git a/spec/policy_factory.rb b/spec/policy_factory.rb
index 3bebeba..cc2cd54 100644
--- a/spec/policy_factory.rb
+++ b/spec/policy_factory.rb
@@ -15,7 +15,7 @@ def user
 end
 
 class DynamicTestPolicy < TestPolicy
-  def method_missing(method, *args, &block)
+  def method_missing(method, *args, &)
     method_s = method.to_s
     return super unless method_s.end_with?('?')