Kicked from the game when reaching y levels over 30,000,000

Deleting both level.dat and the right file in playerdata in the world folder fixes it, but of course it also deletes a lot more. With NBTExporer, you can change the second entry in both level.dat/Data/Player/Pos and playerdata/<UUID>/Pos to fix it.

How did you test that? Teleporting no longer works above the world (no matter if absolute, relative or to an entity), giving a pig that I ride an upwards motion above 10 doesn't work (and with motion 10 it takes almost 42 hours to reach 30 million blocks up). And external editors are not supported on the bug tracker.

It's not actually fixed, but with the teleport coordinated being limited, you can now longer reach the destination easily.
So I'll let Mojang to decide if this issue should remain supported in the future.

I updated the issue with the new reproduction steps.

It's possible again to reproduce this easily in 20w07a alone. It is definitely not fixed.

Since 20w07a, the coordinate values are bounded for x and z, but surprisingly not for y. It is then possible to easy reproduce again just by teleporting to that location.

It is still an issue in 20w11 ?

With NBTExplorer it's pretty easy to test, but that's not valid here. You can teleport to just below 2M and then use the pig method I described before, but that takes 42 hours. I guess I'll let my computer do that over night.

But I don't understand why the report was closed as "awaiting response" even though 07a is listed, that's pretty recent.

It seems as if all players get kicked even if only one of them is above y = 30M (and even when he had logged out). I tested it on a LAN singleplayer world with multiple accounts. But singleplayer is just a local server, could that mean the exploit could be used in order to ban all players? That could be very bad for some servers (other exploits could be used to reproduce the bug, even with commands disabled), and they definitely need to fix it.

I don't know whether multiplayer servers save the player data in the same way that singleplayer does, though. That may need to be tested.

@unknown Did you make that world without modifying save files with external programs? I'm currently in the process of doing that by riding a Motion:[0.0,10.0,0.0] pig, but that takes about 42 hours to do. I'm currently 11819 km high.

You can setup a world in previous snasphot, save the world when you are at 30M - 1. Then load the world in newest snasphot.

I created a world with the Singleplayer player being at y>29999990 in 20w11a alone by riding a pig upwards for 42 hours, thereby answering the question that nobody asked: This bug is not related to upgrading a world from an earlier version.
Here is the world download: https://drive.google.com/file/d/11CLvBWlEo5OMAarprQA4injL4KukLePZ

Should the game just support the player teleporting up to the 10^308 limit or so? The game doesn't exactly break much at high heights anyway.