I looked through the site, google and the EULA for an answer to this. I thought it would be a common question to ask but I haven’t found any mention of it. Though the assumable answer would be “No”, I thought it’s important to know for sure:
If we purchase a Unity pro license right now (While Unity is still in version 3.x), are we able to get Unity 4+ pro (When it comes out) with the same license or would we need to purchase a brand new license? Or is there a small fee to upgrade the license?
Anyway, it’s up to Unity devs to decide these things. For all we know they could release 4.0 for free for current users, or they could ask for a million dollars.
But realistically, there will probably be an upgrade path for 3.x users to 4 and it will probably cost around the 500$ range.
But I think it’s kind of soon to speculate on this. Unity 4 doesn’t feel like it’s very close.
Don’t worry about it, Unity 3 didn’t came out that long ago, it’ll be a while since we even hear about Unity 4 (from actual unity devs). I don’t know what the upgrade price will be, I don’t think it’ll vary much, but consider inflation! X)