diff --git a/crates/dav/src/methods/proppatch.rs b/crates/dav/src/methods/proppatch.rs
index 58de468..93e615b 100644
--- a/crates/dav/src/methods/proppatch.rs
+++ b/crates/dav/src/methods/proppatch.rs
@@ -93,7 +93,14 @@ pub async fn route_proppatch<R: ResourceService>(
                 prop: PropertyElement { prop },
             }) => {
                 if prop.invalid_property() {
-                    props_not_found.push(propname);
+                    if <R::Resource as Resource>::list_all_props().contains(&propname.as_str()) {
+                        // This happens in following cases:
+                        // - read-only properties with #[serde(skip_deserializing)]
+                        // - for read-only properties from extensions
+                        props_conflict.push(propname)
+                    } else {
+                        props_not_found.push(propname);
+                    }
                     continue;
                 }
                 match resource.set_prop(prop) {
diff --git a/crates/dav/src/resource/mod.rs b/crates/dav/src/resource/mod.rs
index 45b1a05..ea6fbe9 100644
--- a/crates/dav/src/resource/mod.rs
+++ b/crates/dav/src/resource/mod.rs
@@ -43,6 +43,17 @@ pub trait Resource: Clone + 'static {
         Self::PropName::VARIANTS
     }
 
+    fn list_all_props() -> Vec<&'static str> {
+        let mut props = Self::list_props().to_vec();
+        props.extend(
+            Self::list_extensions()
+                .into_iter()
+                .map(|ext| ext.list_props().to_vec())
+                .concat(),
+        );
+        props
+    }
+
     fn get_prop(
         &self,
         rmap: &ResourceMap,