I&#x27;ll have to concede the losing sharing. There are still some frustrating things there, the DAV ACL model doesn&#x27;t map very well to the Cyrus model which is based on IMAP permissions and there were a couple of bad bugs in there until recently. We&#x27;re still running patches that I&#x27;d like to remove, but at least we finally understand the cause of lost acls and fixed it.<p>I&#x27;d love to know more about deliverability issues - that&#x27;s something we monitor closely, and we want to know if there are any silent blocks&#x2F;drop rules anywhere that we can&#x27;t monitor for!