PLAYER_JOIN, PLAYER_QUIT

what is it about these two events that is causing so many errors and server crashes, ive seen it with some of my older plugins and i see others listing them as well: could not pass event to *name your outdated plugin*. Have these events been renamed or do they work differently now? is that what the problem is? Can a dev write a brief explanation of why these events dont work anymore? Id like to know if its an easy fix to get some old plugins working again if this is the only problem.