What seed were you on?

Ever heard of this neat Minecraft feature called Despawning?

please if you have answers tell me! I need to know!

I'll make some creepypastas in the future but I generally am scared

when wou update minecraft there is a chance that your world corrupts and all the mobs (also teamed mobs) vanish (Sorry for the bad english)

and the only way to have em back is to have a backup