The new version of UT is in development, almost due for release. It is free to play, and is currently playable.
You will need an Epic Games account in order to download the Epic Games launcher, from within which you will be able to download Unreal Tournament (as well as Unreal Engine 4 if you’re so inclined). You can even contribute to development if you want.
When you’re connected to the ZA Johannesburg hub, there’s a button at the top ‘Download All Content’. Click that to get their custom maps.
It’s not terribly fast.