Pirates of the Burning Sea (abbreviated PotBS) is a massively multiplayer online role-playing game (MMORPG) developed by Flying Lab Software (FLS). The game is set in the Caribbean in an anachronistic 1720 and combines tactical ship battles and swashbuckling combat with a player-driven economy and open-ended gameplay. Pirates of the Burning Sea has been in development since 2002. During the first few years of development, Flying Lab Software realized that this project required more attention than anticipated. Gradually, not only have they more than doubled their staff, but have also put an MMO entitled Delta Green (based on the role-playing game of the same name), on hold. Beta testing began on 14 December 2005, and ran until 1 January 2008. Pre-release started on January 7, 2008 for players who purchased the pre-order. The retail release date was January 22, 2008. The game was formerly subscription-based, but switched to a multi-tiered freemium model on November 22, 2010. Access is also included in Sony Online Entertainment's Station Access, which is a monthly subscription service that provides access to all of SOE's games for a flat monthly fee.