In an effort to get away from using Google services, I finally set up a Baïkal server. I’ve got everything on my phone working well, but when it comes to desktop I’m a little baffled at the lack of more “special dates” support for contacts in my address book. The three I’ve tried so far are Thunderbird, Betterbird, and Evolution.
In all three cases, creating/editing a contact on the client and navigating to special dates only has a birthday and anniversary option. And if I create/edit a contact on my android apps and give them special dates of death anniversary, name day, or other, those dates will simply not appear on the linux clients I have tries so far.
Does anyone know of a CardDAV client for linux with that support?


So, I think you’re bang on here. The exports reveal that the info is included like so:
item1.X-ABDATE:20160302 item1.X-ABLabel:DeathMy cursory searching tells me that this isn’t outside of the CardDAV/vCard spec per se, but that the
X-signifies “extension”, aka basically, info that is being included but may only be read by apps that specifically know to look for it.Now I need to decide if I’d rather have them show up as death anniversaries on my android calendar but not show up at all on my desktop clients, or redo those dates to be maybe a note or something though then they won’t sync to a calendar, or remove it entirely from the contact and instead just have it as an event on my calendar that repeats. Hmm…
Thanks for the idea though, it got me to look at the file itself which was very helpful!