Fabric 1.20

Cannot upgrade backpack in Smithing Table. I put the backpack and the upgrade template in the slots but there is no output.
It could be a mod interaction but I tried disabling my other smithing table-related mods and still cannot upgrade backpack.

standard to iron:

iron to gold:

etc

you have to put leather in template slot, its written in upgrde description

you have to put leather in template slot, its written in upgrde description

Thanks; I don't know how I missed that.
It works with the Iron to Gold, and past that but when I try leather + standard backpack + iron upgrade it tells me "Item can't be upgraded this way" is there something different for the first upgrade?

open backpack, so it'll initiate it's data, then upgrade

you have to put leather in template slot, its written in upgrde description

Thanks; I don't know how I missed that. It works with the Iron to Gold, and past that but when I try leather + standard backpack + iron upgrade it tells me "Item can't be upgraded this way" is there something different for the first upgrade?

I have the same Problem, i can't upgrade with the iron upgrade.
Upgrade with gold, diamond and netherite works
Version: 1.20.1-9.1.9