I can't say for sure because I don't remember if 3.714 and 3.716 connect to each other, but first, check the HD+ mod. It might be enabled on one and disabled on the other, or vice versa. Secondly, it's best to have the same version and update it. Have your friend click the "update HD mod" button in the launcher. Thirdly, in Hamachi, copy the address and, in the game, click "search by IP" and try to connect. Of course, after your friend creates a game (or you create one, and he connects to you). When you can't connect, what does it say? Also, it's possible that someone's firewall or antivirus is blocking the game, like Kaspersky. If nothing helps, try alternative connection methods, like TeamViewer.