Major update

A major update is what the developer of Guild Wars, ArenaNet, calls an update of the Guild Wars game series that adds new locations to the game. Major updates are downloaded automatically as they come out and for free at no hassle to the user.

A major update will usually introduce a few new explorable areas, towns and many quests to the latest chapter and rejuvenate interest in the game.

Major updates so far:
 * In Guild Wars Prophecies: The Sorrow's Furnace update on September 7th, 2005, which introduced two new explorable areas.
 * In Guild Wars Prophecies: The Tomb of the Primeval Kings update on January 19th, 2006 which introduced a new explorable area and moved most PvP content to The Battle Isles.

Major updates are different from chapters in that they are free and their content is simply added to existing content and world map. While both types of releases add more locations, items and quests, chapters can add new professions and skills.

According to Gaile Gray, a major update is currently in production which will add Razah, at least one Elite Mission and the means to reach the highest levels of the Sunspear and Lightbringer title tracks (source).