Exchange 2013, Outlook 2013

we're now moving from 2010 to 2013 Exchange. first thing i noticed, in the server settings of Outlook, the server name changed to some hex numbers@ACME.com where before i used to have "mail.acme.com" there.

is this normal? instead of "mail.acme.com" we now get long-hex-numbers@ACME.com?

Yes this is normal.  Exchange now uses the mailbox GUID@domain.com instead of a shared namespace/name to handle access from Outlook to the mailbox. 

yes its normal and same thing you will find while connecting to office 365 mailbox too.

what's the reasoning for the change? the previous way was much more human readable.