But what happens when you've created a campaign and a new version comes out?
Is all of my work going to be wasted when 3.4 comes out?
when a new version comes out only the core files will change; your mission will still run fine --
there might be some issuses though caused by the changes to core files but they used to be minimal:
eg. when 3.3 was released in the early dev time of AotB everything was fine, except for half of the enemies being no longer present since the table references had changed in only one letter -- but if you know that it was putting it back together will be easy -- (who said one letter would not matter???)
But I once patched up some campaign for TBP I found in the Inet which was supposed to run with releases 1 or 2 (that were still depending on retail FS2) and it wasn't a lot of work since most of code and the tables hadn't changed were it was crutial (except the backgrounds)