diff --git a/.github/workflows/monitor-php8.4.yml b/.github/workflows/monitor-php8.4.yml
index 52b3d1bb..1093f44b 100644
--- a/.github/workflows/monitor-php8.4.yml
+++ b/.github/workflows/monitor-php8.4.yml
@@ -16,6 +16,7 @@ jobs:
         distro:
           - alpine3.19
           - alpine3.20
+          - alpine3.21
           - bullseye
           - bookworm
     name: Check on ${{ matrix.distro }}
diff --git a/.github/workflows/test-extensions.yml b/.github/workflows/test-extensions.yml
index 1d233b8d..2dcaa80e 100644
--- a/.github/workflows/test-extensions.yml
+++ b/.github/workflows/test-extensions.yml
@@ -75,6 +75,7 @@ jobs:
           - alpine3.18
           - alpine3.19
           - alpine3.20
+          - alpine3.21
           - jessie
           - stretch
           - buster
diff --git a/.github/workflows/test-recent-extensions.yml b/.github/workflows/test-recent-extensions.yml
index e6b1d945..e219c175 100644
--- a/.github/workflows/test-recent-extensions.yml
+++ b/.github/workflows/test-recent-extensions.yml
@@ -56,6 +56,7 @@ jobs:
           - alpine3.18
           - alpine3.19
           - alpine3.20
+          - alpine3.21
           - jessie
           - stretch
           - buster