Office 365 and OMWV v11.5 - Will email work?
Replacing Microsoft Outlook 2010 with Microsoft Office 365 (O365) Email. Is this supported? Any problems using Office 365 with Web Viewer?
All, including Windows 2008/2012 R2 Server
There are no known problems between Web Viewer and MS Office 365. We currently run Office 365 2013 here at CA and will be upgrading to a more current level soon. We've encountered no problems emailing from Web Viewer. This answer applies regardless of which supported Web Viewer version you run, and regardless of the Web Viewer platform.
Only if your MAPI interface would change might we expect to see some problem.