Using older versions of Outlook for Mac for personal email and calendar
a mailbox issue just for Mac users? Then they really screwed up
Well, look at this -- mailbox obviously screwed up, so yeah - EWS connection for Legacy Outlook is definitely broken
PS C:> Get-Mailbox MINE | fl *version*
AdminDisplayVersion :
CalendarVersionStoreDisabled : False
ExchangeVersion : 0.20 (15.0.0.0)
PS C:> Get-Mailbox colleague | fl *version*
AdminDisplayVersion : Version 15.20 (Build 7409.32)
CalendarVersionStoreDisabled : False
ExchangeVersion : 0.20 (15.0.0.0)