If you have accounts already set up in Outlook 2016 and have upgraded, then they will continue to work. It's only if you remove/re-add an account or try connecting to a new account that you'll see the issues. For now, the best course of action in these latter situations is to roll back the upgrade to the one prior to 9/12 (16.0.8326.2096)...which is, of course, somewhat of an ordeal...
And yes, there's no mention of it in the release notes for the latest update, and no real mention of the removal of EAS support that we can find. We're looking at options moving forward..trying what we can to get things to continue to work.
In addition, EAS still works perfectly well for mobile devices, which is where Microsoft is focusing efforts, it appears, at least in terms of using EAS.
As for options:
- Windows Mail -- which ships with Windows 10 -- continues to work with EAS.
- eM Client and EWS works well.
- If you want to continue using Outlook, downgrade...or move to IMAP and a webDAV option for calendars and contacts...something like CalDAVSyncronizer.
We're putting the finishing touches on a blog post that covers all of the above and that includes instructions on how to downgrade Outlook 2016. We'll post a link once it's available.