Rated 5 out of 5 stars
Works perfectly with a cyrus carddav server 3.0.8., the UI could be completely adapted to my personal preferences.
Thank you for your work!
For using in an enterprise environment it would be very helpful, to be able to use Kerberos/GSS-SPNEGO - however it seems not implemented.
These days I can use Thunderbird with Kerberos/GSSAPI for IMAP and SMTP, Kerberos/GSS-SPNEGO with caldav Lightning, but for Cardbook I must use username/password.
thanks a lot, will investigate for this (but after the CardBook migration to Thunderbird 68 ;O)