In original D2 you could hotswap/quickswap your mercs gear by dropping an item on their portrait in the corner.
For example, you have an Act 1 merc with equipped with a short bow. You find a hunter’s bow and so you drop the hunter’s bow on her portrait which would equip her with the hunter’s bow and you would be holding the short bow on your cursor. The same also applies to any armor.
This no longer works in 2.4 D2R. I’m not sure if 2.4 itself caused this or if it was a bug prior to that.
It’s the exact same scenario as above, I tried to hotswap a hunter’s bow with her equipped short bow but it doesn’t work. I made sure she meets the stat and level requirements.