It seems that Kolab does not parse .ics META-data corretly:
- iOS device (10.2.1) is connected via active sync to Kolab
- Kolab user gets a meeting invitation - on webmail this shown correctly with RSVP buttons
- on iOS device normally these invitations are shown up as a native message and in inbox of calendar
- with Kolab there are no calendar inbox entries - the .ics attachement is parsed as a regular attachement
- clicking on the attachment allow to add the entry to calendar but without RSVP buttons so the invite won't get any feedback
Tested with own Kolab setup and kolabnow
Own Kolab version: 16.1, debian 8