The questions that come up most. If yours isn't here, check the rules and commands pages, or ask on Discord.
The OldUnreal 227 patch (Classic or Gold). See the Resources section on the main page for the download link.
GameSpy's master server (the thing that populates the in-game server list) shut down in 2014. You'll need to add a working backup master server to your Unreal.ini – see the Master Server Guide linked on the main page. Or just skip the browser entirely and connect directly with unreal://unreal-nostalgia.de:7777.
Double-check you're on the 227 patch first – older/unpatched clients often can't connect to modern coop servers. If that's not it, the server might genuinely be offline – check the live status panel on the main page before assuming it's your setup.
Most mutators and files should download the first time you connect. If auto-download isn't working for you, grab the files manually from the Downloads page and drop them in the right folder – see the file type table there for where each one goes.
No. It's a small self-hosted coop server run for fun, on a Raspberry Pi Zero 2, mostly for people who want to relive the original campaign. See the house rules for the general vibe.
It's running on genuinely minimal hardware (a Raspberry Pi Zero 2), by design. A bit of lag with several players connected is expected, not a bug.
Client-side skins, generally yes. Anything that changes actual gameplay needs to match what the server runs, or you'll likely get kicked for a package mismatch – stick to what's listed on the Downloads page.