diff --git a/Dockerfile b/Dockerfile
index 758db9bcc..bc7cd3b68 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile:1.8
+# syntax=docker/dockerfile:1.9
 
 # This file is designed for production server deployment, not local development work
 # For a containerized local dev environment, see: https://github.com/mastodon/mastodon/blob/main/README.md#docker
diff --git a/streaming/Dockerfile b/streaming/Dockerfile
index d9f7615fa..938f1655d 100644
--- a/streaming/Dockerfile
+++ b/streaming/Dockerfile
@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile:1.8
+# syntax=docker/dockerfile:1.9
 
 # Please see https://docs.docker.com/engine/reference/builder for information about
 # the extended buildx capabilities used in this file.