When using fastmail carddav, with davdroid, i only get read-only access to the contact address book. i have to log into fastmail carddav using the “url” option. It shows my default address book, but it shows it will be read only access.
I have a tablet using aosp android 5, and a stock Samsung s4, running 4.4.4. The situation is the same on both devices.
In using davdroid .7.1