Originally app was meant to be a Electron based app for Windows due to the lack of calendar apps available for this platform. Lately the idea has changed because of the fact that the web version which is possible isn't going to be a lot of different, so there is no point in making app only for Windows platform, while it can works the same as a web application and be available for every operating system. The only one problem is notification support, but this can be bypassed because of the browser support of notifications which are associated with the native operating system notifications. Even speaking that, the idea might evolve later.