diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 75bff07..c7402a7 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -15,7 +15,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@4c56a21280b36d862b5fc31348f463d60bdc55d5 # ruby/setup-ruby@v1 see https://github.com/ruby/setup-ruby/tree/v1
       with:
-        ruby-version: 3.3
+        ruby-version: 4.0
     - name: Install dependencies
       run: bundle install
     - name: Run RuboCop against BASE..HEAD changes
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 5c3c8d0..56e9400 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,13 +15,14 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version:
-          - '3.2'
           - '3.3'
           - '3.4'
+          - '4.0'
         gemfile:
           - gemfiles/Gemfile.rails71
           - gemfiles/Gemfile.rails72
           - gemfiles/Gemfile.rails80
+          - gemfiles/Gemfile.rails81
         exclude:
           # rails 8.0 requires ruby >= 3.2
           # https://www.fastruby.io/blog/ruby/rails/versions/compatibility-table.html
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7572130..5241edd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ## [Unreleased]
-*no unreleased changes*
+### Fixed
+* Support Rails 8.1, Ruby 4.0. Drop support for Ruby 3.2
 
 ## 11.4.1 / 2025-11-05
 ### Fixed
diff --git a/gemfiles/Gemfile.rails81 b/gemfiles/Gemfile.rails81
new file mode 100644
index 0000000..195915c
--- /dev/null
+++ b/gemfiles/Gemfile.rails81
@@ -0,0 +1,5 @@
+source 'https://rubygems.org'
+
+gemspec path: '..'
+
+gem 'activesupport', '~> 8.1.0'
diff --git a/ndr_import.gemspec b/ndr_import.gemspec
index fb4576e..5024153 100644
--- a/ndr_import.gemspec
+++ b/ndr_import.gemspec
@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
 
   spec.add_dependency 'activemodel'
-  spec.add_dependency 'activesupport', '>= 7.1', '< 8.1'
+  spec.add_dependency 'activesupport', '>= 7.1', '< 8.2'
   spec.add_dependency 'ndr_support', '>= 5.3.2', '< 6'
 
   spec.add_dependency 'rubyzip', '~> 2.0'
@@ -39,7 +39,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'seven-zip', '~> 1.4'
   spec.add_dependency 'spreadsheet', '1.2.6'
 
-  spec.required_ruby_version = '>= 3.2'
+  spec.required_ruby_version = '>= 3.3'
 
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake', '>= 12.3.3'