Hello,

All the professional edition (PE) is is the commercial edition (CE) plus some additional extensions such as modules, providers, skins etc. In other words they share the same code (what we term the "open-core"). This means any bug fixes/enhancements are done in a single code base (thought the PE version may have additional enhancements). This also means that if you choose to purchase PE you can upgrade from CE to PE by just installing the PE extensions (i.e. a bunch of zip files)

As to upgrading your current install, you just upgrade as you did before, and can use any versions found on the downloads page. PE users get access to another section of the site where they can download and install the PE version for any release. The good news is that now that DotNetNuke Corp has funding and is making sales, this enables them to hire developers and a large portion of their time is spent working on the opencore e.g. there are now a few people who focus on the monthly maintenance releases, meaning they're more reliable, more regular and will contain more fixes than before, when we relied on people having sufficent spare time to fix stuff. There will also be a lot of new enhancements coming in the next few releases.

Cathal