Starting from version 4.2, EasyFit is available in two editions: Standard and Professional. Both editions include the stand-alone application allowing to fit probability distributions to data, view distribution graphs and properties, perform probability calculations, and make projections/estimates. On top of that, the Professional edition includes the EasyFitXL add-in enabling you to use most of these features right in Excel (compare the editions).
The Standard and Professional editions are delivered as a single download: the installation package will ask you which edition of EasyFit to install. If you install the Professional edition, EasyFitXL will be automatically configured to work with your copy of Excel.
If you purchased EasyFit 4.0 or 4.1, and would like to upgrade, you should choose “EasyFit Professional” during the installation process.