We just upgraded to Exchange 2013 from Exchange 2007. We created and test account from 2007 and was able to migrate the user to 2013 with no issues. Active-Sync is also working for this account with no issues.
When I try to migrate an existing user from 2007 to 2013 its migrates OK, but Active-Sync doesn't work.
When I try to setup the iPhone or Samsung S4 it states that all connections have been made, but it times-out when it tries to download the mail to the phone.