With the mod iron backpack, if you have a basic backpack and put items inside it and you put in the auto crafter to upgrade the backpack for iron backpack, the items that are in the basic will continue and will create an iron backpack with the same items inside
With the mod iron backpack, if you have a basic backpack and put items inside it and you put in the auto crafter to upgrade the backpack for iron backpack, the items that are in the basic will continue and will create an iron backpack with the same items inside
I made this GIF to understand better http://imgur.com/aZaFzaH