diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index cc3200c..3237bd4 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -32,7 +32,6 @@ jobs:
           - rails_6_1
           - rails_6_0
           - rails_5_2
-          - rails_4_2
           - dalli3
           - dalli2
           - redis_5
@@ -56,8 +55,6 @@ jobs:
             ruby: 3.2.2
           - gemfile: active_support_5_redis_cache_store_pooled
             ruby: 3.2.2
-          - gemfile: rails_4_2
-            ruby: 3.2.2
           - gemfile: dalli2
             ruby: 3.2.2
           - gemfile: rack_1
@@ -68,8 +65,6 @@ jobs:
             ruby: 3.1.4
           - gemfile: active_support_5_redis_cache_store_pooled
             ruby: 3.1.4
-          - gemfile: rails_4_2
-            ruby: 3.1.4
           - gemfile: dalli2
             ruby: 3.1.4
           - gemfile: rack_1
@@ -80,14 +75,10 @@ jobs:
             ruby: 3.0.6
           - gemfile: active_support_5_redis_cache_store_pooled
             ruby: 3.0.6
-          - gemfile: rails_4_2
-            ruby: 3.0.6
           - gemfile: dalli2
             ruby: 3.0.6
           - gemfile: rack_1
             ruby: 2.7.8
-          - gemfile: rails_4_2
-            ruby: 2.7.8
           - gemfile: rails_7_0
             ruby: 2.6.10
           - gemfile: rails_7_0
diff --git a/Appraisals b/Appraisals
index 185740d..f68e8b7 100644
--- a/Appraisals
+++ b/Appraisals
@@ -41,14 +41,6 @@ appraise 'rails_5-2' do
   gem 'railties', '~> 5.2.0'
 end
 
-appraise 'rails_4-2' do
-  gem 'railties', '~> 4.2.0'
-
-  # Override rack-test version constraint by making it more loose
-  # so it's compatible with actionpack 4.2.x
-  gem "rack-test", ">= 0.6"
-end
-
 appraise 'dalli2' do
   gem 'dalli', '~> 2.0'
 end
diff --git a/gemfiles/rails_4_2.gemfile b/gemfiles/rails_4_2.gemfile
deleted file mode 100644
index 4209e6d..0000000
--- a/gemfiles/rails_4_2.gemfile
+++ /dev/null
@@ -1,13 +0,0 @@
-# This file was generated by Appraisal
-
-source "https://rubygems.org"
-
-gem "railties", "~> 4.2.0"
-gem "rack-test", ">= 0.6"
-
-group :maintenance, optional: true do
-  gem "bake"
-  gem "bake-gem"
-end
-
-gemspec path: "../"
diff --git a/spec/rack_attack_instrumentation_spec.rb b/spec/rack_attack_instrumentation_spec.rb
index 111ad14..d2291f7 100644
--- a/spec/rack_attack_instrumentation_spec.rb
+++ b/spec/rack_attack_instrumentation_spec.rb
@@ -2,42 +2,38 @@
 
 require_relative "spec_helper"
 require 'active_support'
+require 'active_support/subscriber'
 
-# ActiveSupport::Subscribers added in ~> 4.0.2.0
-if ActiveSupport::VERSION::MAJOR > 3
-  require_relative 'spec_helper'
-  require 'active_support/subscriber'
-  class CustomSubscriber < ActiveSupport::Subscriber
-    @notification_count = 0
+class CustomSubscriber < ActiveSupport::Subscriber
+  @notification_count = 0
 
-    class << self
-      attr_accessor :notification_count
-    end
-
-    def throttle(_event)
-      self.class.notification_count += 1
-    end
+  class << self
+    attr_accessor :notification_count
   end
 
-  describe 'Rack::Attack.instrument' do
+  def throttle(_event)
+    self.class.notification_count += 1
+  end
+end
+
+describe 'Rack::Attack.instrument' do
+  before do
+    @period = 60 # Use a long period; failures due to cache key rotation less likely
+    Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new
+    Rack::Attack.throttle('ip/sec', limit: 1, period: @period) { |req| req.ip }
+  end
+
+  describe "with throttling" do
     before do
-      @period = 60 # Use a long period; failures due to cache key rotation less likely
-      Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new
-      Rack::Attack.throttle('ip/sec', limit: 1, period: @period) { |req| req.ip }
+      ActiveSupport::Notifications.stub(:notifier, ActiveSupport::Notifications::Fanout.new) do
+        CustomSubscriber.attach_to("rack_attack")
+        2.times { get '/', {}, 'REMOTE_ADDR' => '1.2.3.4' }
+      end
     end
 
-    describe "with throttling" do
-      before do
-        ActiveSupport::Notifications.stub(:notifier, ActiveSupport::Notifications::Fanout.new) do
-          CustomSubscriber.attach_to("rack_attack")
-          2.times { get '/', {}, 'REMOTE_ADDR' => '1.2.3.4' }
-        end
-      end
-
-      it 'should instrument without error' do
-        _(last_response.status).must_equal 429
-        assert_equal 1, CustomSubscriber.notification_count
-      end
+    it 'should instrument without error' do
+      _(last_response.status).must_equal 429
+      assert_equal 1, CustomSubscriber.notification_count
     end
   end
 end