diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a0455bf25..b02f6a0a1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,6 +13,12 @@ jobs:
       matrix:
         include:
           # Recent Rubies and Rails
+          - ruby-version: '3.1'
+            rails-version: '7.0'
+          - ruby-version: '3.0'
+            rails-version: '7.0'
+          - ruby-version: '2.7'
+            rails-version: '7.0'
           - ruby-version: '2.6'
             rails-version: '6.1'
           - ruby-version: '2.6'
diff --git a/active_model_serializers.gemspec b/active_model_serializers.gemspec
index 50cd71154..2d1855e8d 100644
--- a/active_model_serializers.gemspec
+++ b/active_model_serializers.gemspec
@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = '>= 2.1'
 
-  rails_versions = ['>= 4.1', '< 7.0']
+  rails_versions = ['>= 4.1', '< 7.1']
   spec.add_runtime_dependency 'activemodel', rails_versions
   # 'activesupport', rails_versions
   # 'builder'
diff --git a/test/action_controller/serialization_test.rb b/test/action_controller/serialization_test.rb
index 8d360b6f8..2286309b4 100644
--- a/test/action_controller/serialization_test.rb
+++ b/test/action_controller/serialization_test.rb
@@ -7,6 +7,7 @@ module Serialization
     class ImplicitSerializerTest < ActionController::TestCase
       class ImplicitSerializationTestController < ActionController::Base
         include SerializationTesting
+
         def render_using_implicit_serializer
           @profile = Profile.new(name: 'Name 1', description: 'Description 1', comments: 'Comments 1')
           render json: @profile
@@ -75,8 +76,12 @@ def render_json_array_object_without_serializer
           render json: [{ error: 'Result is Invalid' }]
         end
 
+        # HACK: to prevent the resetting of instance variables after each request in Rails 7
+        # see https://github.com/rails/rails/pull/43735
+        def clear_instance_variables_between_requests; end
+
         def update_and_render_object_with_cache_enabled
-          @post.updated_at = Time.zone.now
+          @post.updated_at = Time.zone.now # requires hack above to prevent `NoMethodError: undefined method `updated_at=' for nil:NilClass`
 
           generate_cached_serializer(@post)
           render json: @post