WorldTools 1.21.4 updated to 1.21.8 (based on DevoShmokes's Avanatiker/WorldTools#85) and later to 1.21.10 and 1.21.11.
I have little experience with Minecraft modding, but I needed a world download mod that works with the latest Minecraft version. This one does not save player inventory and ender chest properly, but otherwise appears to work correctly (it saves entities and open container data). Grab an up-to-date .jar from releases, or open some PR, I guess.
I don't have time to learn and properly code it, yet I still need the updated version.
Because, again, the code is not perfect/production-ready. This repo is more of a "shared-private" repo, meaning that I will make changes that work for me, and I will not fiddle with it outside of my use case. I put my quick, dirty fixes in this public repo so that others who want 1.21.9+ support can grab the .jar, but that's it.
This repo supports only Fabric on the latest MC version, I will not be maintaining a Forge version or older MC versions.