Raven does not have a dedicated app for iOS, Android or Windows Phone devices. An app for iPhone and iPad was launched in 2010 but was removed from the App Store in 2013, around the same time as a redesign of the software.
Instead of maintaining a mobile app, it is Raven's intention to eventually make the platform mobile responsive, allowing easier use across all devices — including smartphones and tablets. This is a long-term goal that will not be completed for some time. Any news about the responsiveness project will be announced on the Raven blog.