2017-02-06, 13:56
Looks like there are some new tags introduced to iTunes recently
NEW: added support for iTunes-specific ID3v2 grouping tag field GRP1 as GROUPING.
NEW: added support for reading ID3v2.2 iTunes tag fields for classical music MOVEMENT, MOVEMENTTOTAL, MOVEMENTNAME.
Taken from the mp3tag changelog.
http://forums.mp3tag.de/index.php?showtopic=57
NEW: added support for iTunes-specific ID3v2 grouping tag field GRP1 as GROUPING.
NEW: added support for reading ID3v2.2 iTunes tag fields for classical music MOVEMENT, MOVEMENTTOTAL, MOVEMENTNAME.
Taken from the mp3tag changelog.
http://forums.mp3tag.de/index.php?showtopic=57