but incorporates new aircraft such as the Airbus A321, Maule Orion, Boeing 737-800 (replacing the aging Boeing 737-400), Beechcraft King Air and Bombardier CRJ700. The expansion pack, named Acceleration, was released later, which includes new missions, aircraft, and other updates. The Deluxe edition of Flight Simulator X includes the Software Development Kit (SDK), which contains an object placer, allowing the game's autogen and full scenery library to be used in missions or add-on scenery. Finally, the ability to operate the control surfaces of aircraft with the mouse was reintroduced after it was removed in FS2002. Previous versions did not allow great circle navigation at latitudes higher than 60 degrees (north or south), and at around 75-80 degrees north–south it became impossible to "fly" closer to the poles, whichever compass heading was followed. This problem is solved in FSX. Users may now navigate through any great circle as well as "fly" across both the Arctic and Antarctic. This version also adds the option to have a transparent panel. FSX is the first of the series to be released exclusively on DVD-ROM due to space constraints. This is also the first in the series that calls for the preparing process known as activating. Through the internet or a phone a hardware number is generated, and a corresponding code is then used to lock the DVD to one single computer only. It also requires a significantly more powerful computer to run smoothly, even on low graphical settings. Users have reported that the game is "CPU-bound" - a powerful processor is generally more helpful in increasing performance than a powerful graphics card. Meigs Field in Chicago was removed following its sudden destruction in 2003, while Kai Tak Airport in Hong Kong, which had closed in 1998, remained. FSX is the last version of Microsoft Flight Simulator to support Windows XP, Vista, 7, 8, and 8.1 as Microsoft Flight Simulator (2020) only works on Windows 10. Flight Simulator X: Acceleration − Released in October 2007 Microsoft released their first expansion pack for Flight Simulator in years, called Flight Simulator X: Acceleration, to the US market on October 23, 2007, and released to the Australian market on November 1, 2007. Unlike the base game, which is rated E, Acceleration is rated E10+ in the US. Acceleration introduces new features, including multiplayer air racing, new missions, and three all-new aircraft, the F/A-18A Hornet, EH-101 helicopter, and P-51D