Installed Beta 7296 and haven't enabled any of the MAPI features yet, but have witnessed that two of the accounts I use personally are no longer syncing contacts.  One account connects using an Android device - the contacts are gone there but still in webmail.  That account is also setup on my desktop computer in Outlook (using EAS) and the contacts no longer show there either (they had been all along).  The other account connects using an iPhone and its contacts are also gone there.  On my laptop both accounts are setup in Outlook and both using EAS and for both accounts the contacts seem to still be there.  Strange.