There are no immediate plans to bring WriteMapper to Linux and Android. We are however considering adding an iPhone version to the lineup, if there is enough demand shown for it.
None of this is set in stone, however, and we will continue to examine our plans moving forward by looking at our users wants and needs. Should there be sufficient demand for support on any additional platforms, we'll be happy to move forward in adding it to our product lineup.
As of now, WriteMapper is only available on macOS and Windows as a desktop app, and on iOS as an iPad app.
You may download the free trial for the desktop versions here, and get the iPad version from Apple's App Store here.