Genre tagging: using available tag and order sorting

[alan9990]

So I now need to ask:

which is the correct character under ID3v2.4 that Minimserver accepts as NULL?

I read the documentation, and a Wiki page... but either it's '\0' or '\\' or (apparently) CTRL+@ or even CTRL+^ but these are for terminal.

Can anyone please tell me which character, or combination of characters (UTF-8) Minimserver will 'see' as a split?