MP3s: Are XSOP (ID3v2.3) and TSOP (ID3v2.4) handled?

A technical question:

Apart from »Album Artist Sort Order« (TXXX:ALBUMARTISTSORT), I would need an »Artist Sort Order« which is specified in ID3v2.3 as XSOP, in ID3v2.4 as TSOP (Vorbis Comment: ARTISTSORT, APEv2: ARTISTSORT, iTunes MP4: soar, Windows Media: WM/ArtistSortOrder).

Does MP3Tag (v2.41) handle these?

You can try PERFORMERSORTORDER which is mapped to TSOP (and BANDSORTORDER for Album Artist which is mapped to TSO2).

Kind regards,
Florian