I don’t have a previous license for 1.6.x but I do have a license for 2.0. I need to uninstall my 2.0 site and use 1.6 instead due to a module that only supports 1.6.x.
I happened along this post by one of the admins here that says I should be able to use 1.6.x with my 2.x license but I don’t see it in my Downloads.
Lisa Weiss
EE 2 non-commercial and commercial do include EE 1.7 as well, so you do not need to upgrade to EE 2 immediately.