As an on-prem admin, I am blown away that there's 30-40 changes to 365 monthly, often including at least two or three feature deprecations. It seems like building a building on top of quicksand.

  > Microsoft swears it's happening

And when has that ever meant it comes without delay?

Up to you if you believe Microsoft or not. I don't really care, I haven't messed with 365 outside being end user in years.

to be fair with you, EWS has been deprecated since I think 2014, so we're already in the "pushed" window.