Kochkaev's Port to 1.21
I've found this port quite recently and tested it a lot. It has only one bug, you can't refill shadow item stack with hopper. Btw, I'm making this pr to give it an official release, because I heard that many people want this mod to 1.21+, but they can't even find a fork. P.s: I've also made a port for 1.21.3-1.21.4 based on this one, see next pr.
My solution have one rather big problem: client must have a client version of this mod (this mod or ShadowTooltip).
I don’t think it’s a problem. Many people used client versions before 1.21. Why we can’t make client-side required
I've found this port quite recently and tested it a lot. It has only one bug, you can't refill shadow item stack with hopper. Btw, I'm making this pr to give it an official release, because I heard that many people want this mod to 1.21+, but they can't even find a fork. P.s: I've also made a port for 1.21.3-1.21.4 based on this one, see next pr.
I've investigated bug and found that it's only lithium fault. If you want to use carpet shadow and lithium, you have to change mixin.block.hopper to false in lithium.properties.