Cancelling single instance in a recurring series

[SebastianKrupinski]

The issues are mostly in the nextcloud/server code, but I am posting here as logically this is Calendar functionality and most users will search calendar issues first.

Steps to reproduce

1. Create a recurring event
2. Cancel a single instance using the Status in the editor (Do not use delete)

Expected behavior

1. A iTip message should be generated with only the instance cancelled.
2. A iMip message should be sent to participants stating the instance has been updated and an instance has been cancelled. (This debatable, if one or two message should be sent. Technically I think it should be two, one UPDATE for the base event and one CANCEL for the newly created instance as these are technically two separate actions.)

Actual behavior

1. A iTip message is generated but the message wrongly sets the CANCELLED status on the base event.
2. Inbound iTip message processing wrongly applies the CANCELLED status to the base event and not a instance.
3. Due to the above the iMip message shows the entire event cancelled.

Issue

1. The SabreDAV iTipBroker is generating the incorrect iTip messages
2. The ImipPluging needs better handling of recurring instances

[section1]

Hello team.. this bug will be backported to minor version of 31.x ?

[SebastianKrupinski]

Yes the fix will be back ported once it is merged.