diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 04705e4..be4d1bd 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -4,7 +4,7 @@ jobs:
   build:
     strategy:
       matrix:
-        version: ["ruby:3.4", "ruby:3.3", "ruby:3.2"]
+        version: ["ruby:4.0", "ruby:3.4", "ruby:3.3"]
     runs-on: ubuntu-latest
     container: ${{ matrix.version }}
     steps:
diff --git a/.rubocop.yml b/.rubocop.yml
index 26fd590..fe8ec3a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,7 +1,7 @@
 AllCops:
   NewCops: enable
   SuggestExtensions: false
-  TargetRubyVersion: 3.1
+  TargetRubyVersion: 3.2
 Layout/LineLength:
   Enabled: 100
 Metrics/BlockLength:
diff --git a/.ruby-version b/.ruby-version
index f989260..1454f6e 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.4.4
+4.0.1
diff --git a/Gemfile b/Gemfile
index 1c81bb5..476e658 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,4 +17,7 @@ gem 'webmock'
 # Used as a web server for integration testing actual HTTP requests.
 gem 'webrick'
 
+# Used to test logging.
+gem 'logger'
+
 gemspec
diff --git a/lib/reynard/request_context.rb b/lib/reynard/request_context.rb
index 044f5f1..912dc99 100644
--- a/lib/reynard/request_context.rb
+++ b/lib/reynard/request_context.rb
@@ -8,8 +8,7 @@ class Reynard
     :operation,
     :headers,
     :params,
-    :body,
-    keyword_init: true
+    :body
   ) do
     def verb
       operation&.verb
diff --git a/lib/reynard/specification.rb b/lib/reynard/specification.rb
index 04b6481..9695f52 100644
--- a/lib/reynard/specification.rb
+++ b/lib/reynard/specification.rb
@@ -25,8 +25,8 @@ def dig(*path)
     #   specification.find_each(type: 'object') {}
     #
     # Please don't use this in a hot paths in production, primarily meant for testing and tooling.
-    def find_each(type:, &block)
-      Finder.new(specification: self, query: Query.new(type:)).find_each(&block)
+    def find_each(type:, &)
+      Finder.new(specification: self, query: Query.new(type:)).find_each(&)
     end
 
     def servers
diff --git a/reynard.gemspec b/reynard.gemspec
index 82e98d0..b8a769b 100644
--- a/reynard.gemspec
+++ b/reynard.gemspec
@@ -27,7 +27,7 @@ Gem::Specification.new do |spec|
   ]
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = '> 3.1'
+  spec.required_ruby_version = '> 3.2'
 
   spec.add_dependency 'multi_json'
   spec.add_dependency 'net-http-persistent'
diff --git a/test/reynard/object_builder_test.rb b/test/reynard/object_builder_test.rb
index e79a6d6..955b7bd 100644
--- a/test/reynard/object_builder_test.rb
+++ b/test/reynard/object_builder_test.rb
@@ -130,7 +130,7 @@ def setup
   end
 
   class WeirdObjectBuilderTest < Reynard::Test
-    Response = Struct.new(:body, keyword_init: true)
+    Response = Struct.new(:body)
 
     def setup
       @specification = Specification.new(filename: fixture_file('openapi/weird.yml'))
@@ -307,7 +307,7 @@ def setup
   end
 
   class PolymorphicBuilderTest < Reynard::Test
-    Response = Struct.new(:body, keyword_init: true)
+    Response = Struct.new(:body)
 
     def setup
       @specification = Specification.new(filename: fixture_file('openapi/polymorphic.yml'))
diff --git a/test/support/simple_service.rb b/test/support/simple_service.rb
index ac9812e..8801d94 100644
--- a/test/support/simple_service.rb
+++ b/test/support/simple_service.rb
@@ -4,7 +4,7 @@
 require 'webrick'
 
 class SimpleService
-  Options = Struct.new(:port, keyword_init: true)
+  Options = Struct.new(:port)
 
   class Servlet < WEBrick::HTTPServlet::AbstractServlet
     def initialize(*)