Should have said, I actually did:
Maintenance mode on
Backed up DB
Deleted corrupt calendar entry
Maintenance mode off
(In case anyone needs to do the same - always take a backup and always do it while in maintenance mode)
For some calendars I set the ‘force read-only’ option to prevent accidental changes on my android phone.
Every time I select ‘refresh calendar list’ from the davx5 menu then all calendars have the read-only options cleared and I have to set them again manually. I would prefer the option to stick on a refresh.
Thanks, have added it to https://gitlab.com/bitfireAT/davx5-ose/wikis/Roadmap
@rfc2822 thank you very much!