I need to move changes from dev1 instance to dev2 and create upgraded managed package in dev2. I create unmanaged package in dev1 (managed are not allowed there) and try to install to dev2, it shows error about duplicates that come from a previously installed unmanaged package in dev2. So I try to uninstall previous package, and it can't uninstall because there is a component that is referenced by the managed package, the same package that I need to upgrade. It doesn't specify which component. How can I pass changes from dev1 to dev2 in a reasonable way without deleting existing managed package in dev2?