Status of Scheme 48?

Hello there,

I'm considering using Scheme 48 in an embedded application (specifically,
in my game engine), but I would like to know its status -- primarily
whether it is still actively developed or not?

Thing is, I could sleep much more easily if I knew that any bugs I found
would get fixed once reported? I've found it's a real problem with
not-yet-actively-maintained software -- bug reports tend to hit deaf
ears... Or maybe /dev/null, who knows.

Furthermore, I would like to know how well Scheme 48 works in threaded
applications -- I take it the VM does not have any facilities for
simultaneous operation in multiple threads?

Thanks!

Best regards,
Tim Čas