The most recent PC version of yWriter, as of this writing, is yWriter 7, which works on Windows devices running Windows 7 and later, including Windows 10. YWriter started as a Windows app, although it's also available on macOS (in beta), Android, and Apple mobile devices.

This one-time fee is really just a way to support the developer. The higher price entitles you to a discount on Hayes's manuscript evaluation and ebook creation services, but other than that, you don't get any special features or treatment for registering.

A suggested donation of either $11.95 or $24.95 supports the business and registers your app. The app was developed by one person, Simon Hayes, operating under the business name Spacejock. YWriter is totally free to download and use.