diff --git a/dev.yml b/dev.yml
index 3c7e1ff8fd98d4f4eed905678820019c102e577c..1948184b2bc5149b42be9a86cbc086c425254e80 100644
--- a/dev.yml
+++ b/dev.yml
@@ -1,4 +1,4 @@
-version: "3.9"
+version: "3.3"
 services:
   devserver:
     build:
diff --git a/docker-compose.yml b/docker-compose.yml
index 7da79bd5b5c5e20283fc65f985c20a54cc5bcf3f..7b8770da07ceefb2c51e4eddb35c023b87767cbd 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,4 +1,4 @@
-version: "3.9"
+version: "3.3"
 services:
   httpd:
     build: .
diff --git a/traefik.yml b/traefik.yml
index aee5d2df5bab4da9f611546fc2928906b11b8ff0..213c5bc590cd86f0787f4a0d48be1050b1970c33 100644
--- a/traefik.yml
+++ b/traefik.yml
@@ -1,4 +1,4 @@
-version: "3.9"
+version: "3.3"
 services:
   httpd:
     networks: