Hey SiikNic,
there are two versions of Rust. When they released Rust they developed it quite often. I don't knwo why but after some time they just made a completly new "Rust" (for me it's not Rust anymore) and called it experimental. The originel Rust was then called "Old Rust Version" or "Legacy Rust". Nowadays there are still many players and servers left´but the game itself doesn't get any updates anymore.