Upgrading from 1.3 to newest version

We are currently running OCS version 1.3 in our company. We are potentially looking to upgrade to the newest version but do not know if it's worth the trouble. We have about 500+ computer using the service right now.

The problem I'm having is figuring out what's better with the newer version. I can't seem to find a place with release notes or a clear description of what has been added and fixed with newer releases.

Would someone be able to point me in the right direction?

Thanks!