The Platform uses the year and month of the release as the version number. Version 10.3 means that it was out on march 2010.

Version
10.1 First release
10.3 Decoding framework, trace recorders
10.9 Remote Traces, New Installer

For the modules there is a day too. A module with a version number of 10.4.5 has been released april 5th, 2010.