'23 songs will use either the original backtrack or the '14 updated backtrack, whichever is newer in cases of older classics.
From Tsunku's notes: https://note.tsunku.net/n/nfaea90df9e8a
One Two Three ('23)
- Nonaka sang the fakes (wow wo~)
- Added a new chorus line to the A verse and chorus
From Mizuki's blog: https://ameblo.jp/morningmusume-9ki/ent ... 12531.html
Jealousy Jealousy ('23)
- There is a new chorus added to the song that is not heard from the original. Mizuki says she liked it.