The developer Jagex is best known for various versions of RuneScape and shuttering any project that isn’t RuneScape. Ace of Spades is shutting down in July, its FunOrb game portal is shutting down sometime over the next three months, and even Chronicles: RuneScape Legends is being quietly taken down in August. In all three cases, a lack of development resources to address technical errors has been cited for the reason for taking down the games.
There are, however, abundant technical development resources for running the beta for Old School RuneScape‘s mobile version, so that’s still happening with the new always-on Android version. The core of having it always on is just what it sounds like; players can expect the servers to remain on and available at all times, rather than setting a firm end date for the beta testing. If all goes well, more players will be invited over time. So you could theoretically play one version in your phone and one version on the computer, if you really needed to do that for some reason.