I just upgraded from V. 14 to V16.3.6508.  Thought enough bugs might have been worked out.  1st major issue was almost all calendar events in shared calendars were duplicated in Outlook.  So I thought no problem, I'll just delete the duplicates.  Unfortunately, that removed the events entirely from the web interface.  So I thought, no problem, I still have a copy in Outlook and so I renamed the Outlook events, and started to add them back to the web interface.  Except the web interface would not allow creation of multi-day events.  I tried in Firefox and Chrome on a PC.  Same result.  If I try to create or edit an event and make it more than 1 day, it saves and then shows just 1 day instead of many.  If I edit again the event only shows 1 day.  So there definitely seems to be issues with "Day Events" or just calendar issues period.  And my issues are in English!

 

Unfortunately I am probably going to need to revert to an older version . . . these are too serious of issues for production.