Developer reply by Philippe V.
Rated 5 out of 5 stars
Great, that's what I missed a long time. It works fine for me - the Server is a Zimbra Collaboration Server (ZCS).
How to make a donation without PayPal (due to security reasons). What about Bitcoin?
thanks :O) ... to make a donation, send me an email to cardbook.thunderbird@gmail.com... ;O)
To create your own collections, you must have a Mozilla Add-ons account.