The next version will add an option to turn your Markdown tasks into a beautiful Kanban view[2] via QML. This feature will be paid but anyone will be able to compile the source with a simple CMake flag to get the PRO version for free.
Currently, it uses a DB but we aim to port it to support arbitrary folder (simple .md/.json files, depending on the complexity of the editor). I'm working on a mobile version and a built-in sync option as well.
Once the built-in syncing is complete I will probably only charge for that and the client itself will be completely free.