diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 1a7c58e..1e4f05d 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.7', '3.0', '3.1', '3.2', '3.3']
+        ruby-version: ['2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
         gemfile:
           - rails_6_1
           - rails_7_0
@@ -26,6 +26,12 @@ jobs:
           - rails_7_2
           - rails_8_0
         exclude:
+          - ruby-version: '3.4'
+            gemfile: rails_6_1
+          - ruby-version: '3.4'
+            gemfile: rails_7_0
+          - ruby-version: '3.4'
+            gemfile: rails_7_1
           - ruby-version: '3.3'
             gemfile: rails_6_1
           - ruby-version: '3.3'
diff --git a/gemfiles/rails_6_1.gemfile b/gemfiles/rails_6_1.gemfile
index 8248015..87bd039 100644
--- a/gemfiles/rails_6_1.gemfile
+++ b/gemfiles/rails_6_1.gemfile
@@ -2,5 +2,5 @@ source "https://rubygems.org"
 
 gem "rails", "~> 6.1.0"
 gem "sqlite3", "~> 1.4"
-
+gem "concurrent-ruby", "< 1.3.5"
 gemspec path: '../'
diff --git a/gemfiles/rails_7_0.gemfile b/gemfiles/rails_7_0.gemfile
index 6872fb9..9ebf509 100644
--- a/gemfiles/rails_7_0.gemfile
+++ b/gemfiles/rails_7_0.gemfile
@@ -2,5 +2,6 @@ source "https://rubygems.org"
 
 gem "rails", "~> 7.0.0"
 gem "sqlite3", "~> 1.4"
+gem "concurrent-ruby", "< 1.3.5"
 
 gemspec path: '../'