How to check Exchange Version

1. Use About console 

       Open Exchange Management Console > About 

                           

2. Use HUB Console ( CAS/HUB Server)

        Open Exchange Management Console > Server Configuration > Hub Transport OR CAS

                                         

3. Any information related with Version you can see at Microsoft Website:

https://technet.microsoft.com/en-us/library/hh135098(v=exchg.150).aspx