How to support reign-of-kings

This doesn't support Reign of Kings. You can find the available RoK plugins here: https://umod.org/plugins?page=1&sortdir=asc&categories=reign-of-kings&sort=title

Previously supported, and now I see that there are servers using it.

No, there was an entirely different plugin named "Warp System" that isn't currently maintained or published on this site; that wasn't this one.

Is it the one on http://oxidemod.org/?

Once upon a time, yes. There was "Warp System for Rust" and "Warp System for Reign of Kings", two entirely different plugins by different developers.

Thank you. I think I still have it. I need to look for it.