since the update to 9.0.4 I've realised that I cannot share any
addressbook anymore, neither with persons nor group - or at least I
can't find the way to do so. Anything I missed with the change to core
with caldav backend?
Thanks Chris, your questions led to the answer: I had AdBlock activated
on this page and hence the "sharing" icon disappeared, it is now back
functionning. Something worth puting in the DAV documentation for sure!