This is a guide on how to install a free version of UT99 that can be used to play all the old SWAT and TO mod versions.
Follow all steps of the guide before starting the "UT99 Trial Demo" for the first time.
The official UT99 Trial Demo is an old demo from back in the day that would include the full game but only allows you to play for a certain time.
Unreal Tournament Trial Demo.exe
This official patch updates the trial demo to a full UT99 installation. Make sure to not run the Trial Demo before installing this patch.
UT Patch v436 NoDelta.exe
Some of the SWAT or TO maps might require files from these bonus packs that are included in the UT99 GOTY edition but not in the Trial Demo.
Copy an updated OpenGL Renderer into the UT99 System folder.
OpenGL Renderer v3.5.zip
Start the Demo and make sure in the first startup screen to select the OpenGL Renderer.
Else you can also select it afterwards from inside the Video settings in the Preferences menu.
Make sure to set a FPS limit or the game won't run properly.
Information and instructions can be read on the Renderers & Frame Limit guide.
If you want to test multiple SWAT or TO Mod versions it is smart to make a backup/copy of your UT99 folder.
This way you always have a clean base to install any particular version of the mods.