Yes. Updated and space available. Not every sync fails. I’m not sure the source, but in Android 10 I have excluded the app from battery optimization. I’ll see in a few days, If not connection issues, I will return app to battery optimization to see if connections fails reoccur. Thank you.
I installed ICSx5 from Play Store on my Samsung Galaxy S9 running Android 10 (stock). Upon first start, the app did not ask to be whitelisted from battery optimization.
According to FAQ , DAVx5 asks for whitelisting upon first start.
ICSx5, when switching to 4 h sync interval asks for whitelisting as well, but not for 1 day and 1 week sync interval.
In my case with once daily sync:
Battery optimization on, sync does not occur after one day
Battery optimization off, sync works every day.
The remote https-calendar has changes.
For the new user it would help and make the experience better to ask for whitelisting upon first start (for once daily sync).
Thank you for your consideration.
 DAVx⁵ asks to be white-listed when it’s started the first time.
Thx, seems that webdav was used by some apps for users that don’t want to install their own / non-cloud caldav server (e.g. icssync that is no longer maintained).
Found a chinese, closed source alternative (not reliably working, but am desperate):
Or setting up Baikal on Fritzbox, but then all mods will be gone after an update and I guess one is exposed to the internet:
Or google or the closed source, paid / beta https://generalsync.com/de/
All far from perfect, still think the use case of users wanting to sync with their local (ics) files is valid, to avoid the cloud.
However, thanks for the cool & solid DAVx⁵ & ICSx⁵ so far
Hm, I guess the problem is the unescaped ; in the X-APPLE-STRUCTURED-LOCATION line. I don’t think there is an easy way to work around that. Creating a new calendar without that event like suggested by @devvv4ever is probably the best solution.