Thanks Blues News.
The next-generation Unreal engine's network code and file formats are stable enough that we could potentially ship UT(year x) and include the maps from UT(year x-1) and maintain backwards compatibility with existing servers. This obviously couldn't go on forever, but could assure a lifetime similar to UT. Remember, in over 2 years of UT, we only broke network compatibility once.
Anyway, ongoing Unreal Tournament releases aren't an actual plan, just an idea we've been tossing around.