diff --git a/.github/workflows/license.yml b/.github/workflows/license.yml
index 8e8c6f2..e556b83 100644
--- a/.github/workflows/license.yml
+++ b/.github/workflows/license.yml
@@ -7,7 +7,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3
+        ruby-version: '3.4'
     - name: Check license headers
       run: |
         ruby ./.github/check_license_headers.rb
diff --git a/.github/workflows/otel.yml b/.github/workflows/otel.yml
index bcba053..dc80fd9 100644
--- a/.github/workflows/otel.yml
+++ b/.github/workflows/otel.yml
@@ -16,8 +16,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['3.3', 'jruby-9.4']
-        es_version: ['8.15.0-SNAPSHOT']
+        ruby: ['3.4', 'jruby-9.4']
+        es_version: ['8.17.0-SNAPSHOT']
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 153b1b1..ca8f3f5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -15,8 +15,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['3.1', '3.2', '3.3', 'jruby-9.3', 'jruby-9.4']
-        es_version: ['8.15.4-SNAPSHOT', '8.16.0-SNAPSHOT', '8.17.0-SNAPSHOT']
+        ruby: ['3.1', '3.2', '3.3', '3.4', 'jruby-9.3', 'jruby-9.4']
+        es_version: ['8.16.0-SNAPSHOT', '8.17.0-SNAPSHOT', '8.18.0-SNAPSHOT']
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
diff --git a/Gemfile b/Gemfile
index 113de35..b7fc136 100644
--- a/Gemfile
+++ b/Gemfile
@@ -22,6 +22,7 @@ gemspec
 
 group :development, :test do
   gem 'faraday-httpclient'
+  gem 'mutex_m' if RUBY_VERSION >= '3.4'
   gem 'faraday-net_http_persistent'
   gem 'faraday-typhoeus'
   gem 'faraday-excon'
diff --git a/spec/elastic/transport/client_spec.rb b/spec/elastic/transport/client_spec.rb
index a2a8143..967a1f0 100644
--- a/spec/elastic/transport/client_spec.rb
+++ b/spec/elastic/transport/client_spec.rb
@@ -1469,6 +1469,7 @@
 
           context 'when using the HTTPClient adapter' do
             require 'faraday/httpclient'
+            require 'mutex_m' if RUBY_VERSION >= '3.4'
 
             let(:client) do
               described_class.new(hosts: ELASTICSEARCH_HOSTS, compression: true, adapter: :httpclient, enable_meta_header: false)