There are a few ways now! (sorry for necro) there's a few re-writes of the original SCXPM in angelscript (scripting language native to sven co-op).

Much easier to load, doesn't need AMXX to run.

JulianR0 I believe made a full rewrite, Johnboy made one too but the released version is an old unfinished, functions more or less the same but all the advanced stuff like custom weapons is missing from the server, just has the base code.

I also think another person made a rewrite/port of SCXPMto angelscript too.

There's also my plugin I've made, but it's very different to standard SCXPM.

https://github.com/jonnyboy0719/Sven-Coop-RPGMod-Rewrite

https://github.com/JulianR0/CLevels

https://github.com/ChaoticAkantor/CARPG

Of course you can always just install AMXX and download the old SCXPM and it should run just fine, not sure if you still have to swap the metamod install to get it working though. Maybe someone else could help you more with this. Pretty sure it all still works the same.

It's just never been updated since the last v17 or v18 release.

Installing angelscript plugins and running them is much, much faster if you choose to do that instead.

My plugin also uses ZERO custom content, so there's nothing to download from the clients, everything it uses already exists in the base sven install.