Did you upgrade from vB3 to vB4? What happens when vBulletin 5 is released? Will they offer free upgrade to vB5 or will everyone have to buy a license for the new version?
Yes I upgraded my old site from vbulletin 3 to vBulletin 4 which has been out for 2 and a half years. When vBulletin 5 comes out I would need to purchase a new license or renew my old license if I wanted to access it.
Yes ofcourse, you'll need to renew your license to get the latest version.. That's the same with most paid scripts.
vB5 is totally new version, no vB4 or vB4 plugins will work on it. I saw the screen shots and it looks like WordPress theme.
They will give you a discount to upgrade to VB5, but you would still need to pay an amount close to new license holders i'm guessing.