During a "let's improve SparklyPower to make it the best Survival server ever" hyperfixation phase, I've really wanted to update my server to 1.21. I waited eagerly for the shiny Paper experimental 1.21 builds, to update my server right when it is released. Who cares if it is "experimental", after all, what could possibly go wrong?
Well, that was a big mistake.
When the Paper team said that they are experimental builds that you shouldn't run in production, they mean it. The Paper experimental 1.21 builds do not have all of the optimization patches, nor they are stable. But I'm stupid and decided to ignore the experimental label.
Now I'm stuck with a server that could handle ~80 players with 20 TPS on 1.20.6, while on 1.21 it is struggling to keep 20 TPS with only 50 players online. And that makes me sad because it is hard to just shrug it off and carry on when you know that players are sad/angry because the server is lagging, especially because it was entirely my fault. 
<Pantufa> Isn't the solution straightforward? Why not just downgrade the server to 1.20.6 and move on?
Here's the deal: Everyone says that downgrading versions is NOT supported, some even say that it is IMPOSSIBLE to downgrade and that's why you MUST backup your server before updating.
