diff --git a/radicale/storage.py b/radicale/storage.py
index 410ce95..016afb6 100644
--- a/radicale/storage.py
+++ b/radicale/storage.py
@@ -353,7 +353,12 @@ class Collection:
         if os.path.exists(props_path):
             with open(props_path, encoding=STORAGE_ENCODING) as prop_file:
                 properties.update(json.load(prop_file))
-        properties[key] = value
+
+        if value:
+            properties[key] = value
+        else:
+            properties.pop(key, None)
+
         with open(props_path, "w+", encoding=STORAGE_ENCODING) as prop_file:
             json.dump(properties, prop_file)
 
diff --git a/radicale/xmlutils.py b/radicale/xmlutils.py
index beae90c..81d6f28 100644
--- a/radicale/xmlutils.py
+++ b/radicale/xmlutils.py
@@ -442,19 +442,13 @@ def proppatch(path, xml_request, collection):
     href.text = _href(path)
     response.append(href)
 
-    with collection.props as collection_props:
-        for short_name, value in props_to_set.items():
-            if short_name.split(":")[-1] == "calendar-timezone":
-                collection.replace(None, value)
-            collection_props[short_name] = value
-            _add_propstat_to(response, short_name, 200)
-        for short_name in props_to_remove:
-            try:
-                del collection_props[short_name]
-            except KeyError:
-                _add_propstat_to(response, short_name, 412)
-            else:
-                _add_propstat_to(response, short_name, 200)
+    for short_name, value in props_to_set.items():
+        collection.set_meta(short_name, value)
+        _add_propstat_to(response, short_name, 200)
+
+    for short_name in props_to_remove:
+        collection.set_meta(short_name, '')
+        _add_propstat_to(response, short_name, 200)
 
     return _pretty_xml(multistatus)