diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c8df5db..e556729 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,9 +15,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # Rails 7.1 is out of even severe-security support, so the floor is 7.2.
-        ruby: ['3.2', '3.4']
-        rails: ['7.2.0', '8.0.0']
+        # Rails 7.2 reached end of life on 2026-08-09, so the floor is 8.0. Ruby 3.2 went EOL
+        # on 2026-03-31, so the floor there is 3.3 (security-only until 2027-03-31).
+        ruby: ['3.3', '3.4', '4.0']
+        rails: ['8.0.0', '8.1.0']
         activeadmin: ['3.5.0']
     env:
       RAILS: ${{ matrix.rails }}
diff --git a/README.md b/README.md
index 2a31edd..2a5e3f8 100644
--- a/README.md
+++ b/README.md
@@ -143,7 +143,7 @@ Four `prepend`s, no source patching:
 `default:` needs no registration of its own: `add_filter` stores whatever options it is given,
 without a whitelist.
 
-Tested against Active Admin 3.5 on Rails 7.2 and 8.0.
+Tested against Active Admin 3.5 on Rails 8.0 and 8.1, under Ruby 3.3, 3.4 and 4.0.
 
 ## License
 
diff --git a/active_admin_filters_defaults.gemspec b/active_admin_filters_defaults.gemspec
index 6b0c9a1..dc46889 100644
--- a/active_admin_filters_defaults.gemspec
+++ b/active_admin_filters_defaults.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |s|
   s.description = "Lets an Active Admin resource declare what its index filters on when opened " \
                   "without filters of its own: filter :state_eq, default: 'active'"
 
-  s.required_ruby_version = ">= 3.0"
+  s.required_ruby_version = ">= 3.3"
   s.add_dependency "activeadmin", ">= 3.5", "< 4"
 
   s.files         = `git ls-files`.split("\n")
diff --git a/tasks/test.rake b/tasks/test.rake
index b048447..266f4cc 100644
--- a/tasks/test.rake
+++ b/tasks/test.rake
@@ -4,11 +4,15 @@ desc "Creates a test rails app for the specs to run against"
 task :setup do
   require "rails/version"
 
+  # The template throws the generated Gemfile away, so the app runs under this gem's sprockets
+  # bundle with no importmap-rails. Without --skip-javascript, Rails 8.1 writes
+  # `stale_when_importmap_changes` into ApplicationController and booting it raises NameError.
   args = %w[
     --skip-spring
     --skip-bootsnap
     --skip-test
     --skip-system-test
+    --skip-javascript
     -m spec/support/rails_template.rb
   ].join(" ")