The version that SFML works with has nothing to do with the version(s) that one can request with sf::ContextSettings. With the desktop implementation, you can request a context that won't support sfml-graphics (a forward compatible one, for example), which is ok if you only use sfml-window.
So even if the mobile ports are based on OpenGL ES 1, nothing prevents from adding the ability to give other versions on demand. It's just a little more work.