Confusion about version information on jars and source code release

[Casty]

Hi, there. 

I think it may be a rather simple question. However, just to solve my confusion.

I wonder why the version of the jars I downloaded from the Maven repository says 313, is short for 3.1.3. ? The latest version of the source code release seems to be  2.9.5. 

Aren't they supposed to be the same? I am really confused about it.

Any help will be appreciated. Thanks a lot!