The MoO2 version that's most widely used now from GoG.com/Steam is actually a fan made bug fix patched version, but some of the bugs it fixes are rather useful to speedrunners, and there are pretty significant rule changes in version 1.3 and above.
If you still have the game CD (and the ability to run it), you can get the official patches for the base 1.1 version from Archive.org:
MoO2 v1.2 patch https://archive.org/details/moo2v12
MoO2 v1.3 patch https://archive.org/details/MOO2V13
MoO2 v1.31 patch https://archive.org/details/MOO2V131
Put the installer in the same folder as the game install and double click. Press "y" to run it.
Version 1.2 is probably the most useful. It's more stable on modern OSes than 1.1, and you have access to the 6 point Creative race pick and pre-nerf Gyro Destabilizers, which are useful for fast Guardian kills and Antarian kills. The Guardian and Antarians are both much weaker in this version generally. This version also seem to improve the function of the Auto Battle Hotkey "z". It's faster and doesn't cause as many graphical glitches.
Version 1.3 contains some interesting AI changes. They're much more aggressive than in the fan patch, but they're also a lot stupider. I'd always wondered if it was possible to just get lucky and be elected Emperor in the first few turns, and I'd guess it might be possible on this version. This is also the first version with all modern Hotkeys available.
Version 1.31 is probably not terribly interesting to speedrunners. It does fix the AI bugs from 1.3 however.
I'd tend to agree. The only category that I'm very sure using an older version saves time on is Orion%. The changes to the Guardian and the Gyro destabilizer tech being more powerful usually makes for research-less Guardian killing.
Antaran%? I have no damn clue! There's so many ways I can think of to do it with the hotkey optimizations and different tech that it's probably equal if not much faster on later versions! And Any% is almost assuredly faster on 1.40b23 due to hotkey optimizations.
Hey! I would like to maybe try the Antaran% run. Is it fine to play it with the 1.50 mod?
It's fine to play on that version, however since the 1.50 patch is not officially sanctioned, not included in any official release like 1.40b23, and adds significant features / makes significant changes, we'd likely have to give it it's own variable and separate runs out.
That shouldn't stop you if you want to do runs on the modded version though! Please feel free to post a completed run on 1.50 here in this thread and I'll add a place for the modded versions of each of the runs to the board!