Support Proppatch Method

The PROPPATCH method is used to set properties on collections. Some CalDAV implementations are likely to issue a MKCOL first and then a PROPPATCH to make it into a calendar collection. Most other properties are potentially settable with PROPPATCH.

Additional CalDAV Calendar Collection properties
At this point, while it is possible to set & remove these properties with PROPPATCH it is not possible to query them with PROPFIND.