For the next update of WriteFlow we decided to completely move to 10.6 (Snow Leopard) and not try to support 10.5 (Leopard) anymore.
This decision comes as the result of tight resources, but also in view of the upcoming 10.7 (Lion) release. It will be very advantageous for us and for our users to implement some features which are Lion only.
Especially some new features for CoreData and some improvements with Fullscreen mode will make our lives easier. The next update will include a new Command Tool with better text support and Spotlight search.
By the way, I would like to encourage you to buy a license of WriteFlow now. You can significantly speed up development, with your feedback we can adapt WriteFlow to your own personal workflow, and you’ll be able to follow the unfolding of the full potential of the WriteFlow technology form a front seat.