There are quite a few changes in this release. Most prominent being the ability to change mods at runtime and play background music from files (ogg, mp3, flac, wav). There's some nice enhancements behind the scenes too with improved texture cache management and host of minor bug fixes.

Changelog:

• Added (finally) loading new mods at runtime with the 'game' command.
• Added ability to play music tracks from sound files. Currently ogg (vorbis), mp3, flac and wav are supported.
• Add some auto-detection of quake installation directory (windows). If the game is started without specifying the base directory and the working directory is not a valid basedir, the game will try to check if you have a copy of Quake in Steam and use that.
• Improved console tab completion for commands with multiple arguments
• Fixed overflowing the sound effects cache
• Improved detection of local network address
• Improved reliability of game discovery via broadcast on LANs
• Fixed fullbright textures on player skins
• Added a pulseaudio sound driver, now the default on Linux.
• Fixes for minor audio artifacts in looping sounds
• Fix crash in NQ dedicated server
• Higher quality (resolution) underwater warping in software renderer
• Fix particle sizes in software and GL
• Make a fixed size LRU cache of textures in GLQuake and free unused textures

Download from the TyrQuake page.