Mod loader and version-
Minecraft 1.16.5
forge 36.2.39
travelers-backpack-1.16.5-5.4.38.jar

Copy the upgrade module

"To upgrade from version 5.4.35 to 5.4.38

1.Put the backpack on the ground
2.Hold the blank upgrade in your hand, then aim at the backpack and press shift+right click, you can copy the upgrade module infinitely"

log:https://netcut.cn/travelers-backpac

could you record a video?

你能录制视频吗？

I have a backup of the server, I can record a video for you, but I live in Asia, I need to sleep.
Where should I upload the video?

you can upload where you want

您可以在您想要的地方上传

I went back to my old save, but I can’t seem to reproduce the issue of duplicating upgrade modules. It seems like I can only provide you with that log for now.
But I encountered a new problem. When the player dies in water or lava or void, the backpack on their back does not spawn in a safe place, but disappears directly. It is not stored in GraveStone. Since the backpack on the ground will generate uuid when dying, is there a command to regenerate the backpack on the player?

yes, you can restore backpack with /restore command