Exchange Server 2010 had about 22 ActiveSync-related cmdlets; those named *-ActiveSync*, such as Get-ActiveSyncDevice.
Exchange Server 2013 added two new *-ActiveSync* cmdlets; Get-ActiveSyncDeviceAutoblockThreshold and Set-ActiveSyncDeviceAutoblockThreshold. Those cmdlets basically give us the ability to automatically block “bad behaviour” from mobile devices such as the infamous iOS 6.1 bug.
In addition to those two new cmdlets there are also 8 new cmdlets that somewhat replicate the same functionality of the 8 corresponding cmdlets that have been deprecated.
An example of this is Get-ActiveSyncDevice which has been deprecated, and a new cmdlet Get-MobileDevice steps in to take its place. The deprecated cmdlets still work, but they warn you that they may disappear in future versions of Exchange so if you're relying on them for scripting you will need to update your scripts accordingly.
Get-MobileDevice does basically the same thing as the previous cmdlet, though it has a new OWAMobileApp parameter that is “reserved for future use”.
For a full list of the new cmdlets here is a table showing the comparison between Exchange 2010 and Exchange 2013.