I have contacts stored in ownCloud with PHOTO and other fields like X-GENDER and BDAY. After making changes to a contact on the phone those fields have disappeared in ownCloud. DAVDroid should keep fields it doesn’t know.
The Problem (Challange) i have a old nextcloud-server and set up a new one - but can’t move the Adress from the old to the new.
so my idea was to edit each Contact i have an move it into the new Adressbook which then would nicely sync back with DAVx5 to the new Nextcloud.
Absolutely no problem exists to export an Nextcloud address book to an csv file and re-import it into a new server. I would recommend to go the easy way.
The same way exists on an Android phone if you e.g. use the Google Contacts app.