Thank you very much for the answer!
CalDAV Sync doesn't handle recurring event modifications correctly with Horde
I’m using Horde as my CalDAV server, and I’ve done things such as the following:
Have a long-time recurring event, such as daily work schedule that repeats every M-F at the same times. For holidays and days off, I would delete those days for that specific event in the calendar, yet DAVdroid would re-add it at sync. If I delete it for 1 occurance in my local Android calendar, Horde would show it still but struck out.
Another scenario in that same thing, I modified a recurring event, same one, to have an end time. When android synced, it deleted the entire schedule.
There’s definitely some issues when dealing with recurring events, at least with Horde. I have yet to check this out in any other CalDAV server (such as I also use owncloud, but rarely sync with it anymore, mostly files).
I had to go back to using Marten Gajda’s CalDAV-Sync for the time being to resolve this issue temporarily, as it works, in that respect, fully without issues with recurring event calendars.
I have similar problems -but I’m using “Kolab Groupware”. If I create a recurring event and modify a single event of this set (e.g. change the name or the duration) then DavDroid does not Update/Sync this change to my mobile phone.
Further problems exist in the context of deleting a single event of such a row - I observe the same behavior as described by @erenfro
If you need more information -please let me know
Thanks for your report.
Duplicate of #170, please follow up there.