The chance for mobs to drop a spell book when killed. The greater this number, the more often they will drop. Set to 0 to disable spell book drops. Set to 200 for guaranteed drops.

I:spellBookDropChance=

There were setting options in the previous 4.1.4 version, why is it not in the new version now?I don't want monsters to drop spellbooks in the server

It's done using loot tables now, which is significantly more customizable and powerful, but also more complex to configure. See https://github.com/Electroblob77/Wizardry/blob/1.12.2/src/main/resources/assets/ebwizardry/loot_tables/entities/mob_additions.json

Thank you