diff --git a/roles/docker/defaults/main.yml b/roles/docker/defaults/main.yml
index ee348a0..75e15e4 100644
--- a/roles/docker/defaults/main.yml
+++ b/roles/docker/defaults/main.yml
@@ -44,7 +44,7 @@ services:
     domain: sso.{{ base_domain }}
     volume_folder: "{{ volume_root_folder }}/keycloak"
     version: "20.0"
-    postgres_version: 10
+    postgres_version: "10"
     allowed_sender_domain: true
 
   restic:
@@ -70,7 +70,7 @@ services:
     domain: "cloud.{{ base_domain }}"
     volume_folder: "{{ volume_root_folder }}/nextcloud"
     version: 25-apache
-    postgres_version: 10
+    postgres_version: "10"
     redis_version: 7-alpine
     allowed_sender_domain: true
 
@@ -86,7 +86,7 @@ services:
     domain: "passit.{{ base_domain }}"
     volume_folder: "{{ volume_root_folder }}/passit"
     version: stable
-    postgres_version: 10
+    postgres_version: "10"
     allowed_sender_domain: true
 
   matrix:
@@ -94,7 +94,7 @@ services:
     domain: "matrix.{{ base_domain }}"
     volume_folder: "{{ volume_root_folder }}/matrix"
     version: v1.63.1
-    postgres_version: 10
+    postgres_version: "10"
     allowed_sender_domain: true
 
   riot: