I intend to use 7-zip as a utility in my product which I sell to customers. 7-zip will be shipped to them, along with my software, and 7-zip will need to perform some duties at the client side. Are there any legal issues to this ? Since 7-zip is free, I think I am allowed to use it .. but I want to be sure. Also, what happens if this piece of software ceases to be a freeware in the future ? Will i be able to use my old version ? Or will will I be forced to buy a license