Can you tell me what kind of product. The 4 version surely is a standard engine (SE). But the seven could be a SE or an IDS. Can you alsospecifu the full version numbers, something like SE 7.25.UC2 or IDS 7.31.UD4
Upgrading between SE version 4 and 7 ins't that big a problem, upgrading from SE 4 to IDS 7 is no upgrade but a product change. (But you'll notive a lot of performance gain in the last situation).
Sorry, but without the product type (SE/IDS) I can't give you any hints/tips.