It's based on AmigaOS4.0! :-)
What it's based on is is the OS3.1 sourcecode and whatever OS3.9 sourecode Amiga managed to scrap together for Hyperion.
Could you please refrain from making assumptions? I do recall hearing that Amiga Inc has no source code. And thats from unofficial contacts. I could be wrong as this was 4 years ago.
OS4/4.1 is based indeed on source code from os3.1/3.9. But it came from another source, not A Inc.
