Hi, when you purchase a Gunbot license you can use any past, present or future versions. So it doesn't matter if you used v3 or v7, with a Gunbot license you are able to run any Gunbot version. You will even be able to download and run any future version for free.
The thing is what pack did you purchase (Gunbot Standard, Gunbot Pro, Gunbot Ultimate etc...). Contact your reseller, he should be able to tell you what pack did you purchase. In the case you can't contact him, I would be able to figure out what pack did you purchase if you could tell me the api key you activated when you made the purchase.