[haspoken]

I'm in the same boat. Work email is now hosted off-prem by microsoft and per microsofts suggestion, imap has been disabled

A few things to check out:

  Outlook web client - Microsoft abuses it though if not hosted on-prem and it has a few major bugs if you don't use the default settings.  

  Evolution-ews is a version of the evolution email client that will work with exchange.

  DavMail Gateway might be worth a look http://davmail.sourceforge.net/index.html

  Owl for Exchange - a plugin for thunderbird that is supposed to be os independent.

  You might also use alternativeto.net for more suggestions.