Crossword Man's releases are numbered M.N where M is the version number and N is the update number. For example, 2.4 means update 4 of version 2. You can use the About... command on the Help menu to confirm which release you have installed.
Customers can download unlimited free updates of the product version they originally purchased. For example, if you purchased update 2.3 of a product, you can download updates 2.4, 2.5 etc for free as they appear.
When the scope of a product increases substantially, the product version (the number before the decimal point) is changed and there is usually an increase in the product price. Existing customers can buy the new product version at a substantial discount.
The What's New page shows information about the latest releases. You can also find out about new releases by subscribing to the relevant mailing list in the Support section of the Crossword Man site.