Quickie question - have upgraded my first (of 3) zen servers to version 7.

I understand that when I fire up C1 with the new Zen7 snapins and "touch" the apps, policies etc they are auto upgraded with the new zen attributes etc.

Will this have an impact on my userbase who are still using the old zen 4.01 agent on their PCs. Will these upgraded apps still deploy etc to these machines. Do I need to upgrade all my clients with the new agent before firing up C1 with the new snapins. I'd like to start testing the the upgraded features etc but am wary about causing issues for my current Zen 4.01 userbase.

Grateful for your help!!!