diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index fabcbe2..768aaeb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.0', '3.1', '3.2', '3.3']
+        ruby-version: ['3.3', '3.4', '4.0']
 
     steps:
     - uses: actions/checkout@v4
@@ -37,7 +37,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.0', '3.1', '3.2', '3.3']
+        ruby-version: ['3.3', '3.4', '4.0']
 
     steps:
       - uses: actions/checkout@v4
diff --git a/.rubocop.yml b/.rubocop.yml
index 6e22451..069012c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,10 +1,10 @@
-require:
+plugins:
   - rubocop-performance
   - rubocop-rake
 
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 3.0
+  TargetRubyVersion: 3.3
 
 Metrics/MethodLength:
   Max: 30
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fabaac8..d78f4b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased](https://github.com/soundasleep/html2text_ruby/compare/v0.4.0...master)
+### Changed
+- Require Ruby 3.3+; CI now tests Ruby 3.3, 3.4 and 4.0 ([#42](https://github.com/soundasleep/html2text_ruby/pull/42))
+- Update development dependencies (rubocop 1.88, nokogiri 1.19 in the lockfile), removing the transitive `rexml` dependency ([#42](https://github.com/soundasleep/html2text_ruby/pull/42))
 
 ## [0.4.0](https://github.com/soundasleep/html2text_ruby/compare/0.3.1...v0.4.0) - 2024-06-08
 ### Added
diff --git a/Gemfile.lock b/Gemfile.lock
index 0543b78..6974188 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,27 +7,32 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    ast (2.4.2)
+    ast (2.4.3)
     bundler-audit (0.6.1)
       bundler (>= 1.2.0, < 3)
       thor (~> 0.18)
     colorize (0.7.7)
     diff-lcs (1.3)
-    json (2.7.2)
-    language_server-protocol (3.17.0.3)
-    mini_portile2 (2.8.7)
-    nokogiri (1.16.5)
+    json (2.20.0)
+    language_server-protocol (3.17.0.6)
+    lint_roller (1.1.0)
+    mini_portile2 (2.8.9)
+    nokogiri (1.19.4)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    parallel (1.24.0)
-    parser (3.3.2.0)
+    nokogiri (1.19.4-arm64-darwin)
+      racc (~> 1.4)
+    nokogiri (1.19.4-x86_64-linux-gnu)
+      racc (~> 1.4)
+    parallel (2.1.0)
+    parser (3.3.11.1)
       ast (~> 2.4.1)
       racc
-    racc (1.8.0)
+    prism (1.9.0)
+    racc (1.8.1)
     rainbow (3.1.1)
-    rake (12.3.3)
-    regexp_parser (2.9.2)
-    rexml (3.3.9)
+    rake (13.4.2)
+    regexp_parser (2.12.0)
     rspec (3.8.0)
       rspec-core (~> 3.8.0)
       rspec-expectations (~> 3.8.0)
@@ -43,30 +48,37 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.8.0)
     rspec-support (3.8.0)
-    rubocop (1.64.1)
+    rubocop (1.88.2)
       json (~> 2.3)
-      language_server-protocol (>= 3.17.0)
-      parallel (~> 1.10)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
+      parallel (>= 1.10)
       parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 1.8, < 3.0)
-      rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.31.1, < 2.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.49.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.31.3)
-      parser (>= 3.3.1.0)
-    rubocop-performance (1.21.0)
-      rubocop (>= 1.48.1, < 2.0)
-      rubocop-ast (>= 1.31.1, < 2.0)
-    rubocop-rake (0.6.0)
-      rubocop (~> 1.0)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.50.0)
+      parser (>= 3.3.7.2)
+      prism (~> 1.7)
+    rubocop-performance (1.26.1)
+      lint_roller (~> 1.1)
+      rubocop (>= 1.75.0, < 2.0)
+      rubocop-ast (>= 1.47.1, < 2.0)
+    rubocop-rake (0.7.1)
+      lint_roller (~> 1.1)
+      rubocop (>= 1.72.1)
     ruby-progressbar (1.13.0)
     thor (0.20.3)
-    unicode-display_width (2.5.0)
+    unicode-display_width (3.2.0)
+      unicode-emoji (~> 4.1)
+    unicode-emoji (4.2.0)
 
 PLATFORMS
+  arm64-darwin
   ruby
+  x86_64-linux
 
 DEPENDENCIES
   bundler-audit
diff --git a/html2text.gemspec b/html2text.gemspec
index 4385634..4a29d3d 100644
--- a/html2text.gemspec
+++ b/html2text.gemspec
@@ -15,7 +15,7 @@ Gem::Specification.new do |s|
   s.summary     = 'Convert HTML into plain text.'
   s.description = 'A Ruby component to convert HTML into a plain text format.'
   s.license     = 'MIT'
-  s.required_ruby_version = '>= 3.0'
+  s.required_ruby_version = '>= 3.3'
 
   s.files = Dir['lib/**/*', 'LICENSE.md', 'README.md', 'CHANGELOG.md']