You can upgrade anything from 1.20 and on directly to the latest versions. I recently upgraded a 1.2 set with the 1.6 and 1.7 versions. I'm bringing an extra set of modules with 1.6 and 1.7 to York. If anyone is trying to get the latest set, bring a couple of writable modules and I'll swap you. I know a lot of folks don't have the ability to download the files and write the modules.