Mail/Calendar client for Exchange server OAuth2

I've been using Thunderbird with the Exchange calendar provider to use email and calendar from my employer's Office 365 setup. However as of 10/15 it appears Microsoft will only be allowing OAuth2 connections, and the Exchange provider does not support that.

Is there a viable mail and calendar client that will handle OAuth2 to allow Office365 as the backend? Strong preference for FLOSS, but I'd be willing to go commercial if necessary.

Thanks.