Ok, so the other threads are going nowhere... One person loves 2.5, the other one hates it. Fact is, now I dunno what you guys want, so I don't know what to do with the servers. So, here's a poll: The poll will run until I get back from my honeymoon, which is the 11th of may, so let's say 14 days.
I don't know if serverside modifications are possible and to what extend, but if it isn't it can be done clientside and the second option: "2.5 with 2.4.2 nexgun and sounds (if possible!)" will be counted as votes for "2.5". Someone, perhaps myself or Lost, should be able to create a .pk3 for it.
Like I said before, leaving the servers at version 2.4.2 doesn't mean they'll stay 2.4.2 forever, we can re-evaluate this after some time and turn them into 2.5 servers eventually...