In the Infocenter for each of the releases, there is a section on version-to-version changes. There are several related to Windows. Please see the Infocenter for the appropriate version:
V6.0 to V7.5 Changes
V6.0 to V7.1 Changes
There is a V7.0 Infocenter but at this point, everyone should be migrating to V7.5 preferably, or V7.1 at the earliest, due to the security enhancements and other features.