diff --git a/Dockerfile b/Dockerfile
index 24a7c91..99d3153 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.16
+FROM alpine:3.21
 LABEL Maintainer="Tim de Pater <code@trafex.nl>" \
       Description="Lightweight WordPress container with Nginx 1.22 & PHP-FPM 8.0 based on Alpine Linux."
 
diff --git a/docker-compose.test.yml b/docker-compose.test.yml
index 487e051..bf4a474 100644
--- a/docker-compose.test.yml
+++ b/docker-compose.test.yml
@@ -23,7 +23,7 @@ services:
       FS_METHOD: direct
 
   sut:
-    image: alpine:3.16
+    image: alpine:3.21
     depends_on:
       - wordpress
     command: /tmp/run_tests.sh