diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index eae636a3..37aece03 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,9 +14,9 @@ jobs:
     strategy:
       matrix:
         ruby:
-          - "3.2"
           - "3.3"
           - "3.4"
+          - "4.0"
       fail-fast: false
 
     steps:
diff --git a/github-markup.gemspec b/github-markup.gemspec
index c8c1d3ad..7a02478e 100644
--- a/github-markup.gemspec
+++ b/github-markup.gemspec
@@ -13,7 +13,7 @@ Gem::Specification.new do |s|
   s.homepage      = "https://github.com/github/markup"
   s.license       = "MIT"
 
-  s.required_ruby_version = '>= 3.1.0'
+  s.required_ruby_version = '>= 3.3.0'
 
   s.files         = `git ls-files`.split($\)
   s.executables   = s.files.grep(%r{^bin/}).map{ |f| File.basename(f) }