Guild Wars 2: Heart of Thorns is the first expansion pack for Guild Wars 2 , a massively multiplayer online role-playing game developed by ArenaNet and published by NCSOFT . It was released for Microsoft Windows on October 23, 2015. It was made available for pre-purchase on June 16, 2015. [4] After the release date was broadcast on August 29, 2015, the base game was made free-to-do play , free players have less character slots and have restrictions on mailing and chatting with other players. [5]