@davvi We have reported the problem to Synology on 6 Dez 2015 (Synology Support Ticket: #712664). To report read/write privileges, CalDAV uses WebDAV ACL.
Bug when importing a .vcf contact from messages
When I receive a .vcf contact card in a SMS, and click on it, I am prompted the contacts account to save the contact to. If I choose the local phone contacts, or a gmail account, it works and the contact is imported. If I choose a DavDroid account, I get a message such as “The contacts app crashed” (this is a translation, maybe not the exact english error). The contact is not imported.
Sony XPeria Z1 Compact, D5503, Android KitKat 4.4.4
I cannot reproduce this. Seems to be a bug of your Contacts app. Please contact your Contacts app vendor.
If there’s any indication that this might be related to DAVdroid, please post it here.
The contacts app is the stock Android Contacts. Importing to any contact account (yahoo, gmail, internal) other than DAVDroid works, so this is not that clear.