diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 206a69d..7782634 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,7 +14,7 @@ jobs:
       matrix:
         # Due to https://github.com/actions/runner/issues/849, we have to use
         # quotes for '3.0' -- without quotes, CI sees '3' and runs the latest.
-        ruby: [2.4, 2.5, 2.6, 2.7, '3.0', 3.1, 3.2, jruby, truffleruby-head]
+        ruby: [2.5, 2.6, 2.7, '3.0', 3.1, 3.2, jruby, truffleruby-head]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed4826c..e325dba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,14 +5,23 @@ follows a format inspired by [Keep a Changelog](https://keepachangelog.com/en/1.
 
 This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased](https://github.com/panorama-ed/memo_wise/compare/v1.8.0...HEAD)
+## [Unreleased](https://github.com/panorama-ed/memo_wise/compare/v1.9.0...HEAD)
+
+**Gem enhancements:**
+
+_No breaking changes!_
+
+**Project enhancements:**
+
+## [v1.9.0](https://github.com/panorama-ed/memo_wise/compare/v1.8.0...v1.9.0)
 
 **Gem enhancements:**
 
 - Fixed a bug that overwrote existing self.extended method definitions. [[#324]](https://github.com/panorama-ed/memo_wise/pull/314)
 - Fixed a bug that overwrote existing self.inherited method definitions. [[#325]](https://github.com/panorama-ed/memo_wise/pull/315)
 
-_No breaking changes!_
+_Breaking changes:_
+- Removed Ruby 2.4 (EOL) support to allow upgrading rexml dependency version from a version that includes a [CVE](https://www.ruby-lang.org/en/news/2024/05/16/dos-rexml-cve-2024-35176/) [[#336]](https://github.com/panorama-ed/memo_wise/pull/336)
 
 **Project enhancements:**
 
diff --git a/Gemfile.lock b/Gemfile.lock
index d1d00d9..a460152 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,7 @@ GIT
 PATH
   remote: .
   specs:
-    memo_wise (1.8.0)
+    memo_wise (1.9.0)
 
 GEM
   remote: https://rubygems.org/
@@ -33,7 +33,8 @@ GEM
     rake (13.1.0)
     redcarpet (3.6.0)
     regexp_parser (2.8.0)
-    rexml (3.2.5)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rouge (4.1.0)
     rspec (3.13.0)
       rspec-core (~> 3.13.0)
@@ -82,6 +83,7 @@ GEM
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
     slop (3.6.0)
+    strscan (3.1.0)
     unicode-display_width (2.4.2)
     values (1.8.0)
     webrick (1.8.1)
diff --git a/README.md b/README.md
index ccbabd3..8096f1a 100644
--- a/README.md
+++ b/README.md
@@ -118,15 +118,15 @@ Results using Ruby 3.2.2:
 
 |Method arguments|`Dry::Core`\* (1.0.1)|`Memery` (1.5.0)|
 |--|--|--|
-|`()` (none)|0.60x|3.58x|
-|`(a)`|1.37x|7.41x|
-|`(a, b)`|1.20x|6.43x|
-|`(a:)`|1.47x|13.60x|
-|`(a:, b:)`|1.20x|10.55x|
-|`(a, b:)`|1.21x|10.36x|
-|`(a, *args)`|0.79x|1.52x|
-|`(a:, **kwargs)`|0.77x|2.02x|
-|`(a, *args, b:, **kwargs)`|0.69x|1.38x|
+|`()` (none)|0.66x|3.54x|
+|`(a)`|1.48x|8.49x|
+|`(a, b)`|1.18x|6.52x|
+|`(a:)`|1.53x|13.57x|
+|`(a:, b:)`|1.27x|10.56x|
+|`(a, b:)`|1.26x|10.44x|
+|`(a, *args)`|0.78x|1.60x|
+|`(a:, **kwargs)`|0.77x|2.12x|
+|`(a, *args, b:, **kwargs)`|0.69x|1.40x|
 
 \* `Dry::Core`
 [may cause incorrect behavior caused by hash collisions](https://github.com/dry-rb/dry-core/issues/63).
@@ -135,15 +135,15 @@ Results using Ruby 2.7.8 (because these gems raise errors in Ruby 3.x):
 
 |Method arguments|`DDMemoize` (1.0.0)|`Memoist` (0.16.2)|`Memoized` (1.1.1)|`Memoizer` (1.0.3)|
 |--|--|--|--|--|
-|`()` (none)|22.09x|2.35x|23.72x|2.60x|
-|`(a)`|20.98x|14.43x|21.20x|12.20x|
-|`(a, b)`|17.45x|12.94x|17.69x|11.13x|
-|`(a:)`|29.80x|23.38x|25.17x|21.57x|
-|`(a:, b:)`|27.00x|22.26x|23.30x|20.91x|
-|`(a, b:)`|25.91x|21.20x|21.88x|19.51x|
-|`(a, *args)`|3.07x|2.27x|3.17x|1.95x|
-|`(a:, **kwargs)`|2.74x|2.28x|2.51x|2.10x|
-|`(a, *args, b:, **kwargs)`|2.14x|1.84x|1.95x|1.72x|
+|`()` (none)|22.57x|2.27x|23.46x|2.63x|
+|`(a)`|20.96x|14.29x|20.54x|11.97x|
+|`(a, b)`|18.22x|13.21x|17.76x|11.34x|
+|`(a:)`|30.66x|23.52x|25.37x|21.61x|
+|`(a:, b:)`|27.31x|21.98x|23.02x|20.31x|
+|`(a, b:)`|26.21x|20.85x|21.57x|19.20x|
+|`(a, *args)`|3.06x|2.23x|3.10x|1.92x|
+|`(a:, **kwargs)`|2.67x|2.18x|2.39x|2.02x|
+|`(a, *args, b:, **kwargs)`|2.14x|1.80x|1.89x|1.70x|
 
 You can run benchmarks yourself with:
 
diff --git a/lib/memo_wise/version.rb b/lib/memo_wise/version.rb
index 2511cc8..d30d3bc 100644
--- a/lib/memo_wise/version.rb
+++ b/lib/memo_wise/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module MemoWise
-  VERSION = "1.8.0"
+  VERSION = "1.9.0"
 end
diff --git a/memo_wise.gemspec b/memo_wise.gemspec
index 7d5fe41..6c951a6 100644
--- a/memo_wise.gemspec
+++ b/memo_wise.gemspec
@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
     "marc@usainnov.com",
   ]
 
-  spec.required_ruby_version = Gem::Requirement.new(">= 2.4.0")
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.5.0")
 
   # Specify which files should be added to the gem when it is released.
   # The `git ls-files -z` loads the files in the RubyGem that have been added