diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index af73ab211..84a37d58d 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -25,7 +25,7 @@ steps:
             transport: main
     env:
       RUBY_VERSION: '{{ matrix.ruby }}'
-      STACK_VERSION: 9.3.0-SNAPSHOT
+      STACK_VERSION: 9.4.0-SNAPSHOT
       ES_YAML_TESTS_BRANCH: main
       TRANSPORT_VERSION: '{{ matrix.transport }}'
       RUBY_SOURCE: '{{ matrix.ruby_source }}'
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 668ed52e3..b59676122 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -28,7 +28,7 @@ jobs:
         sudo sysctl -w vm.max_map_count=262144
     - uses: elastic/elastic-github-actions/elasticsearch@master
       with:
-        stack-version: 9.3.0-SNAPSHOT
+        stack-version: 9.4.0-SNAPSHOT
     - uses: ruby/setup-ruby@v1.263.0
       with:
         ruby-version: ${{ matrix.ruby }}
diff --git a/.github/workflows/otel.yml b/.github/workflows/otel.yml
index 5a328d9cf..fec79dc65 100644
--- a/.github/workflows/otel.yml
+++ b/.github/workflows/otel.yml
@@ -30,7 +30,7 @@ jobs:
           sudo sysctl -w vm.max_map_count=262144
       - uses: elastic/elastic-github-actions/elasticsearch@master
         with:
-          stack-version: 9.3.0-SNAPSHOT
+          stack-version: 9.4.0-SNAPSHOT
       - uses: ruby/setup-ruby@v1.263.0
         with:
           ruby-version: ${{ matrix.ruby }}