New chapter Kase-san and Sunflowers : 25 new pages (plus 1 title page) flashback
New chapter Kase-san and Powder Snow : 33 new pages (plus 1 title page) the week before Kase goes to Tokyo, also Yamada initiates (!)
These can be read in Yamada and Kase-san.
Should those be put here instead, since we now know they're part of volume 5? Or would that just cause confusion? Maybe with an explanatory note wherever they aren't listed, so people don't think they're missing... not that anyone reads such things, mind you.
Also, I've done some research (ie: found the volume raws online), and as well as having two chapters with the same number, volume 4 is out of order. It should go:
Tulips
Apron
Crêpe (with a circumflex)
Present
Plant Appointee
Also also, a favourite scene of Borderline Hand-holding
for no particular reason.