trying to update my mod pack from 1.20.4 to 1.21.4

[upbeat sinew]

I tried to update but when I launch it nothing happens. here is the log https://mclo.gs/sZQwNR6

[gilded linden]

UnionLib is for the wrong mc version

[storm cloak]

u can't just throw 1.20 mods into 1.21.4

U have to recreate the entire pack, using 1.21.4 updated mods

This is litterly the bane of EVERY modpack creator ever.

Especically me... who has 700 Mods on 1.19.2 and i can't update to 1.21 since all the mods don't yet exist on 1.21

[gilded linden]

-# packwiz