in January 2005. PrBoom PrBoom is a Doom source port derived from Linux and Windows ports of Boom and MBF that includes an optional OpenGL renderer, as well as options allowing it to restore the behavior of earlier executables (such as Doom version 1.9, Boom, and MBF) in essential ways. A variation named PrBoom+ provides enhanced demo recording and viewing capabilities. PrBoom was used as the engine for id Software's official port for the iPhone, Doom Classic. The source port is packaged in the Ubuntu Software Center as well as Fedora's RPM software repository alongside Freedoom. PrBoom was last updated on November 9, 2008. Although PrBoom and PrBoom+ are simpler than some other Doom source ports, they are often preferred as staying relatively close to the behavior of the original games, and have good demo support. However, some of the bug fixes and behavior changes of other ports may unbalance how levels made for the original games play, giving players certain advantages or disadvantages. Doomsday Engine and derivatives The Doomsday Engine is a GPLv2-licensed source port (incorporating the former jDoom, jHexen, and jHeretic) that runs on Linux, Mac OS X, and Windows. The source port also supports Heretic, Hexen: Beyond Heretic and Doom II. Its hardware-accelerated engine supports 3D models, dynamic lighting, object and movement smoothing, shadows, and other features. It also includes XG line and sector types for editing extensions, as well as a built-in master server games browser (launcher). Vavoom Vavoom is a source port created by merging the Doom, Heretic, and Hexen: Beyond Heretic source trees to create a unified executable. It also features bits of the Quake source code (used predominantly for networking and rendering), and was the first source port to support Strife: Quest for the Sigil. It has been in development since September 1999, and was first released on June 14, 2000. Among its features are a true 3D polygonal engine with colored lighting and software, Direct3D and OpenGL renderers, freelook support, 3D floors, and support for Boom's extended attributes. The source port is packaged in the Fedora RPM software repository alongside free installers that grab the shareware levels for all the games used by the engine by default. ZDoom and derivatives ZDoom is a source port launched for Windows on March 6, 1998, and later Linux and macOS. It supports Boom editing extensions plus all of the extensions made in the version of