jupp development has been split into two active development lines: jupp for DOS (based on joe 2.8) and jupp for Unix (based on joe 3.x).
There are binaries for both DOS (jupp for DOS) and Win32 (jupp for Unix, via Cygwin) available.
The jupp for DOS development line incorporates only minor patches relative to the original source code (it wasn’t that buggy as the sourceforge development made the code later…) and a jupprc file tuned for it but feature-complete with joe-3.1jupp10’s one.
The jupp for Unix development line incorporates all of the very extensive patches to the binary, and an enriched jupprc with, due to popular demand, syntax highlighting enabled by default – even though I still loathe it personally, and feel with Rob Pike when he questions the use of pretty printers. It will also try to correctly guess CR-LF vs LF-only line endings, indentation, and terminal colour. Furthermore, the language selection of the jupp flavour is now en par with that of the joe flavour, and the Python variants honour the standard coding style of theirs (needed that by the third quarter of last year, remember?). Autoindent is still off, by default, though – with reason.
Now give it a try. Hint: ^J (Ctrl-J) invokes the help.