diff --git a/src/mock_vws/_flask_server/Dockerfile b/src/mock_vws/_flask_server/Dockerfile
index ed1a39479..19d145087 100644
--- a/src/mock_vws/_flask_server/Dockerfile
+++ b/src/mock_vws/_flask_server/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.12-slim as base
+FROM python:3.12-slim AS base
 # We set this pretend version as we do not have Git in our path, and we do
 # not care enough about having the version correct inside the Docker container
 # to install it.