diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 14a1962..793fd85 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,9 +2,9 @@ name: CI
 
 on:
   push:
-    branches: [ "master" ]
+    branches: [ "main" ]
   pull_request:
-    branches: [ "master" ]
+    branches: [ "main" ]
 
 permissions:
   contents: read
@@ -15,10 +15,10 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.7', '3.0', '3.1']
+        ruby-version: ['3.2', '3.3', '3.4']
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
diff --git a/Gemfile.lock b/Gemfile.lock
index 90136a8..7fdf1e1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,10 +6,10 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    minitest (5.16.3)
-    power_assert (2.0.1)
-    rake (13.0.6)
-    test-unit (3.5.5)
+    minitest (5.25.5)
+    power_assert (2.0.5)
+    rake (13.2.1)
+    test-unit (3.6.8)
       power_assert
 
 PLATFORMS
@@ -23,4 +23,4 @@ DEPENDENCIES
   test-unit (~> 3.0)
 
 BUNDLED WITH
-   2.3.7
+   2.6.2
diff --git a/README.md b/README.md
index 4c46449..e5264c5 100644
--- a/README.md
+++ b/README.md
@@ -33,24 +33,9 @@ Or install it yourself as:
 
 ## Compatibility
 
-`structured_warnings` aims to work with all Ruby interpreters. Please file a bug
-for any incompatibilities.
-
-
-Versions of `structured_warnings` before `v0.3.0` are incompatible with Ruby
-2.4+. Please upgrade accordingly, if you need Ruby 2.4 compatibility. Please
-note on the otherhand, that many class names changed in an incompatible way
-with `structured_warnings` `v0.3.0`. This was done to avoid future name clashes.
-
-Here's a table which should ease upgrading.
-
-| v0.2.0 and before            | v0.3.0 and after                                 |
-|------------------------------|--------------------------------------------------|
-| `Warning`                    | `StructuredWarnings::Base`                       |
-| `StandardWarning`            | `StructuredWarnings::StandardWarning`            |
-| `DeprecationWarning`         | `StructuredWarnings::DeprecationWarning`         |
-| `DeprecatedMethodWarning`    | `StructuredWarnings::DeprecatedMethodWarning`    |
-| `DeprecatedSignatureWarning` | `StructuredWarnings::DeprecatedSignatureWarning` |
+`structured_warnings` aims to work with all stable, maintained Ruby versions. At
+the time of this writing this is Ruby 3.2, 3.3, and 3.4. Please file a bug for
+any incompatibilities.
 
 
 ### Test framework support
diff --git a/lib/structured_warnings.rb b/lib/structured_warnings.rb
index ad70348..12c8a92 100644
--- a/lib/structured_warnings.rb
+++ b/lib/structured_warnings.rb
@@ -1,8 +1,5 @@
 require 'structured_warnings/version'
 
-# Compatibility layer
-require 'warning' unless defined? ::Warning
-
 require 'dynamic'
 
 module StructuredWarnings
diff --git a/lib/structured_warnings/kernel.rb b/lib/structured_warnings/kernel.rb
index 1419977..359c505 100644
--- a/lib/structured_warnings/kernel.rb
+++ b/lib/structured_warnings/kernel.rb
@@ -1,6 +1,6 @@
 module StructuredWarnings::Kernel
-  def warn(*args)
-    Warning.warn(*args)
+  def warn(*args, **opts)
+    Warning.warn(*args, **opts)
   end
 end
 
diff --git a/lib/structured_warnings/warning.rb b/lib/structured_warnings/warning.rb
index 591114f..06e5c2a 100644
--- a/lib/structured_warnings/warning.rb
+++ b/lib/structured_warnings/warning.rb
@@ -36,7 +36,7 @@ module StructuredWarnings::Warning
   #
   #   warn StructuredWarnings::Base.new("The least specific warning you can get")
   #
-  def warn(*args)
+  def warn(*args, **options)
     first = args.shift
     if first.is_a? Class and first <= StructuredWarnings::Base
       warning = first
@@ -52,11 +52,9 @@ def warn(*args)
 
     else
       warning = StructuredWarnings::BuiltInWarning
-      message = first.to_s.split(':', 4).last[1..-2]
+      message = first.to_s.split(':', 4).last.strip
     end
 
-    options = args.first.is_a?(Hash) ? args.shift : {}
-
     # If args is not empty, user passed an incompatible set of arguments.
     # Maybe somebody else is overriding warn as well and knows, what to do.
     # Better do nothing in this case. See #5
diff --git a/lib/warning.rb b/lib/warning.rb
deleted file mode 100644
index 9eab49b..0000000
--- a/lib/warning.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-module Warning
-  KERNEL_WARN = Kernel.instance_method(:warn).bind(self)
-
-  def warn(*args)
-    KERNEL_WARN.call(*args)
-  end
-
-  extend self
-end
diff --git a/structured_warnings.gemspec b/structured_warnings.gemspec
index 684ad85..fca07c1 100644
--- a/structured_warnings.gemspec
+++ b/structured_warnings.gemspec
@@ -18,6 +18,8 @@ Gem::Specification.new do |spec|
 
   spec.require_paths = ['lib']
 
+  spec.required_ruby_version = '>= 3.2.0'
+
   spec.add_development_dependency 'bundler', '~> 2.1'
   spec.add_development_dependency 'rake', '~> 13.0'
   spec.add_development_dependency 'minitest', '~> 5.0'
diff --git a/test/structured_warnings_test.rb b/test/structured_warnings_test.rb
index 86b98ed..d663b81 100644
--- a/test/structured_warnings_test.rb
+++ b/test/structured_warnings_test.rb
@@ -25,6 +25,22 @@ def method_using_incompatible_warn_api
     end
   end
 
+  def opening_quote
+    if RUBY_VERSION < '3.4'
+      '`'
+    else
+      "'"
+    end
+  end
+
+  def classname_in_message
+    if RUBY_VERSION < '3.4'
+      ''
+    else
+      'StructuredWarningsTest#'
+    end
+  end
+
   def test_fork_in_thread
     return unless supports_fork?
 
@@ -128,8 +144,6 @@ def test_base_is_default_warning
   end
 
   def test_builtin_warnings
-    return unless supports_core_warnings?
-
     with_verbose_warnings do
       assert_warn(StructuredWarnings::BuiltInWarning, /method redefined; discarding old name/) do
         class << Object.new
@@ -213,7 +227,7 @@ def test_formatting_of_warn
 
     expected_warning =
       "#{__FILE__}:#{__LINE__ - 4}:" +
-      "in `block in test_formatting_of_warn': " +
+      "in #{opening_quote}block in #{classname_in_message}test_formatting_of_warn': " +
       "do not blink " +
       "(StructuredWarnings::StandardWarning)\n"
 
@@ -230,16 +244,8 @@ def test_formatting_of_warn_with_uplevel
     end
 
     expected_warning =
-      "#{__FILE__}:#{__LINE__ - 4}:"
-
-    expected_warning +=
-      if RUBY_VERSION < '2.3'
-        "in `call': "
-      else
-        "in `block in test_formatting_of_warn_with_uplevel': "
-      end
-
-    expected_warning +=
+      "#{__FILE__}:#{__LINE__ - 4}:" +
+      "in #{opening_quote}block in #{classname_in_message}test_formatting_of_warn_with_uplevel': " +
       "do not blink " +
       "(StructuredWarnings::StandardWarning)\n"
 
@@ -247,8 +253,6 @@ def test_formatting_of_warn_with_uplevel
   end
 
   def test_formatting_of_builtin_warn
-    return unless supports_core_warnings?
-
     actual_warning = capture_strderr do
       class << Object.new
         attr_accessor :name
@@ -261,13 +265,27 @@ def name
 
     expected_warning =
       "#{__FILE__}:#{__LINE__ - 7}:" +
-      "in `singleton class': " +
+      "in #{opening_quote}singleton class': " +
       "method redefined; discarding old name " +
       "(StructuredWarnings::BuiltInWarning)\n"
 
     assert_equal expected_warning, actual_warning
   end
 
+  def test_formatting_of_manual_warn
+    actual_warning = capture_strderr do
+      Warning.warn("This is a test warning.")
+    end
+
+    expected_warning =
+      "#{__FILE__}:#{__LINE__ - 4}:" +
+      "in #{opening_quote}block in #{classname_in_message}test_formatting_of_manual_warn': " +
+      "This is a test warning. " +
+      "(StructuredWarnings::BuiltInWarning)\n"
+
+    assert_equal expected_warning, actual_warning
+  end
+
   protected
 
   def supports_fork?
@@ -280,10 +298,6 @@ def supports_fork?
     false
   end
 
-  def supports_core_warnings?
-    Warning.instance_method(:warn).source_location.nil?
-  end
-
   def with_verbose_warnings
     verbose, $VERBOSE = $VERBOSE, true