In order to optimize the server performance, several changes have been made which could alter the way mob farms work. The most notable changes are as follows:
The hostile mob cap is per-player rather than per-world.
The entity cramming limit is set to 8.
The soft despawn range is 28 and the hard despawn range is 96.
The view distance is 4.
Villagers will run their acquirepoi behavior 25% as often as vanilla.
Zombies are not aggressive towards villagers.
A chunk will only save up to 1 hopper minecart, 1 of any individual projectile, and 16 of any individual passive mob type. Any extras will despawn when the chunk is unloaded.
Entities that are far from players tick less often, and the distance varies for each mob.
Piglin runs on Purpur which might slightly toy around with technical details but aims to be as close to vanilla as possible.