diff --git a/.github/workflows/microbenchmark.yml b/.github/workflows/microbenchmark.yml
index 043b89ab9..0e4a0c677 100644
--- a/.github/workflows/microbenchmark.yml
+++ b/.github/workflows/microbenchmark.yml
@@ -5,7 +5,7 @@ on:
     inputs:
       stack_version:
         description: 'Stack Version'
-        default: '8.6.1'
+        default: '8.9.1'
         required: false
   push:
     branches:
@@ -28,7 +28,7 @@ jobs:
         name: Run buildkite pipeline
         uses: elastic/apm-pipeline-library/.github/actions/buildkite@current
         env:
-          STACK_VERSION: ${{ inputs.stack_version || '8.6.1' }}
+          STACK_VERSION: ${{ inputs.stack_version || '8.9.1' }}
         with:
           vaultUrl: ${{ secrets.VAULT_ADDR }}
           vaultRoleId: ${{ secrets.VAULT_ROLE_ID }}