Upgrade from 6.20 to 6.40

We are currently trying to justify the upgrade from 6.20 to 6.40.

What are the added benefits/fucntionality of thre upgrade?? I have checked on sap.com on the comaprison guide, but it is not available.

Can anyone point me in the right direction? Or just list some benefits for me?

Regards

Barry Neaves

SAP Developer