I've been searching for 365 requirements for Mac devices and I found that the minimal mail client is one of the following:
Microsoft Outlook for Mac 2011 SP1
Microsoft Entourage 2008 WSE
Microsoft Outlook Web App
Do we have the same functionality for Apple Mail?
Same thing for the OS, I foud Macintosh OS X 10.5.8 or later. But what would be the minimum iOS version?