This is a test version incorporating all of the latest server-side stability and performance improvements. It's backwards compatible with Unreal 224 clients. If you're running a 224 server and are experiencing performance or stability problems, please upgrade. If you experience any server problems or server crashes with 225, please email your Unreal.log file to email@example.com so we can investigate the problems. The results on our test server here at Epic indicate that this version is significantly faster (i.e. supports more players) than 224, and is more stable but I don't expect it to be perfect, because I rewrote about a thousand lines of server code to improve performance, and there will probably be some bugs to shake out.
Only download this if you are running an Unreal server: UnrealPatch225e.exe.
The general Unreal 225 patch for everybody including users will be available in a few days.