I like openoffice, but I find the calendar feature quite unusable as our main calendar.
1) the calendar cannot be synced with other clients, like mail/calendar apps on android, ios or even windows. Caldav functionality to sync calendars, address books and tasks is really needed. Also ITIP/IMIP invitation scheduling (RSVP) is needed.
2) but even within openoffice the calendar app is not so useable: if I make a group event, the group members have no option to accept or decline the invitation, so you never know who shows up.
3) It should be possible to make a calendar event directly from an email or task.
4) a last remark: the word "event " is used within onlyoffice for several total different things (for announcements, for calendar events, in CRM, etc.) this is confusing. so best to use different words for different functionalities.
Is onlyoffice adressing these issues?