I downloaded and installed Firefox 3.1 on Kernelex 0.3.6 Win98se modded with Auto-Patcher and 98SP3. Firefox 3.1 installs fine once you tell setup you have XP in the INI file for Kernelex but the program has two problems.

Both are font-related issues and both are solvable by removing compatibility.ini from Firefox 3.1's profile folder before you start Firefox. You must do this every time you start firefox, so make a batch file and use that instead . I also do not know if this had anything to do with my fix but I found it while using Profile Manager at each startup (the /profilemanager option), which can be added to a shortcut or batch file if necessary. Finally, I do not know if this method applies to or is needed on Firefox 3.0.x.

Overall it is important for many to use the latest version of the Firefox browser, and although running 3.1 on 98se is mostly for kicks now, in the future (assuming the trick still works on 3.1 final) this will be important to run the latest web apps.

I think, that instead of creating new thread, the better idea was putting this valuable information in the KernelEx thread - I'm pretty sure that Xeno and Tihiy would be grateful for that.