Most GPL projects do this. I don't have access to my box, but if you did a search for licenses you'd find many use "or later" (and in fact a lot of code within

Most GPL projects do this. I don't have access to my box, but if you did a search for licenses you'd find many use "or later" (and in fact a lot of code within Linux uses "or later" as well). So practically it's a very common upgrade path. And some people will actually email every contributor to ask to relicense the code.