diff --git a/Containers/collabora/Dockerfile b/Containers/collabora/Dockerfile
index 411a3edf..a80b1fba 100644
--- a/Containers/collabora/Dockerfile
+++ b/Containers/collabora/Dockerfile
@@ -11,7 +11,9 @@ RUN set -ex; \
         tzdata \
         netcat-openbsd \
     ; \
-    rm -rf /var/lib/apt/lists/*
+    rm -rf /var/lib/apt/lists/*; \
+    mkdir -p /opt/cool/child-roots; \
+    chmod 777 -R /opt/cool/child-roots
 
 USER 100
 
diff --git a/php/containers-schema.json b/php/containers-schema.json
index 84343317..df828f5e 100644
--- a/php/containers-schema.json
+++ b/php/containers-schema.json
@@ -141,7 +141,7 @@
 						"type": "array",
 						"items": {
 							"type": "string",
-							"pattern": "^/[a-z/_]+$"
+							"pattern": "^/[a-z/_-]+$"
 						}
 					},
 					"volumes": {
diff --git a/php/containers.json b/php/containers.json
index ad5c2bd7..f969e3ff 100644
--- a/php/containers.json
+++ b/php/containers.json
@@ -294,6 +294,10 @@
       ],
       "networks": [
         "nextcloud-aio"
+      ],
+      "read_only": true,
+      "tmpfs": [
+        "/opt/cool/child-roots"
       ]
     },
     {