Over time, expansions have added features such as conquerable and constructible space stations, massive capital ships, advanced versions of existing ships, or "Epic Arcs" for players to master. Apocrypha included an overhauled probing system, wormholes, a smarter and tougher AI and customizable Tech 3 ships as its major features. Dominion, which became available for download on December 1, 2009, included an overhaul of the sovereignty system, more realistic astronomy, the Titan Doomsday weapon functionality being changed and the in-game web browser with Chromium's WebKit. It also included a redesign of the UI and in-game mailing system. Tyrannis added new features, such as the ability to exploit planetary resources, a social networking program called EVE Gate, new technology for ships, and graphical updates.