We have tried to use and promote the use of WebDAV among our users and try to use the Carddav Caldav included in Smartermail but  there are many issues with the current WebDAV implementation. (Smartermail 16.x)

Both Caldav and carddav work erratically on MacOS.  Ive tried the Apple apps like Calendar and Contacts and SM fails to update correctly in many occasions.  Also, there is no way to "invite" others via the Apple Calendar, which should be an essential part of the CalDAV implementation.

 

Then we switched to BusyCal and BusyContacts and the same thing happens.  (In this case, we are able to create invites from the BusyCal app, but syncing is a nightmare)  

 

Every other cardav/caldav implementation we have works perfectly (iCloud, Google) except the WedDAV with Smartermail.   Smartertools team, I would kindly request that you really dig into your implementation, add whatever features are part of a successful implementation, and make sure it works fine for future releases. Thanks.