Previously we were running Spigot, which is a fork of CraftBukkit, which is a fork of bukkit which is a fork of the original vanilla server software :D
Paper (which is a fork of Spigot) should help us with some of the background issues we are dealing with. We have been tracking down some memory leaks on the server that have caused major lags towards the end of the day.
We recently disabled all the spawn chunks which has drastically helped keep the server lag free for the most part, but even with these changes we still see the server start to struggle.
We have been asking around for help with these issues and it is clear that most of the people that reply recommend switching to paper, so here we are
What is Spigot