When you purchase a WinGate license, you purchase the features available at the time. When a version is released with new features in it then they will be locked for an earlier version license. So you can always expect to use the features you originally bought as well as the maintenance provided to those features when a new version is released.
What's the purpose to renew the wingate v.6.x
So you receive Version Protection - which means you will be licensed for new features that are released; a number of new ones will be available in WinGate 2007.
why wingate need to renew
If the Version Protection is renewed within 90 days before the previous expiry then it will cost 25% of the list price. If the Version Protection is renewed after the expiry then it will cost 40% of the list price.
wingate is not one time license fee
When you purchase a WinGate license, you purchase the features available for that license type at the time.