diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index d58f4d5..1d669f2 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,8 +15,6 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
         version:
           [
-            2.5,
-            2.6,
             2.7,
             '3.0',
             3.1,
diff --git a/.rubocop.yml b/.rubocop.yml
index 237ca14..b71a2fc 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,5 +1,5 @@
 AllCops:
-    TargetRubyVersion: 2.5
+    TargetRubyVersion: 2.7
     NewCops: enable
 
 # Metrics.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58870a4..72e0890 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## v2.4.0
+
+* Ruby 2.7+ is now required. If you're using Ruby 2.5 or 2.6, please use
+  version 2.3.0 of this gem.
+
 ## v2.3.0 (2023-12-04)
 
 * Added the processor `:shopify_payments` to `Minfraud::Components::Payment`.
diff --git a/README.md b/README.md
index d608d6d..3591281 100644
--- a/README.md
+++ b/README.md
@@ -275,7 +275,7 @@ to the client API, please see
 
 ## Requirements
 
-This gem works with Ruby 2.5 and above.
+This gem works with Ruby 2.7 and above.
 
 ## Contributing
 
diff --git a/minfraud.gemspec b/minfraud.gemspec
index cf965bb..f99f84f 100644
--- a/minfraud.gemspec
+++ b/minfraud.gemspec
@@ -15,7 +15,7 @@ Gem::Specification.new do |spec|
   spec.homepage      = 'https://github.com/maxmind/minfraud-api-ruby'
   spec.license       = 'MIT'
 
-  spec.required_ruby_version = '>= 2.5.0'
+  spec.required_ruby_version = '>= 2.7.0'
 
   spec.files         = `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
   spec.bindir        = 'exe'