Fallout Shelter, a free-to-play base builder launched on PC in 2017, has received its largest update yet, introducing a new season pass system. This update includes content previously exclusive to the mobile version, such as new questlines, characters, weapons, and themes. The first season pass, titled 'Viva New Vegas,' features limited-time 'experimental vaults,' familiar characters, outfits, and rewards to enhance vault dwellers' morale. Players can also engage in the 'Power Struggle' questline with eight missions and new characters. The update celebrates the 25th anniversary of Fallout with a six-quest chain 'Searching in the Dark' and introduces new vault dwellers and adversaries. The base season pass is priced at £10, with additional premium content available for another £10. The update is now live on Steam, allowing players to enjoy the game for free.