The first public release of Impulse Engine, or more specifically, Impulse Legacy. Impulse Legacy is a branch off from the mainstream Impulse code. Legacy is built to keep Legacy support with Quake based games (eg. Quake, HeXen II etc.) Along with keeping support for Quake engine based games, It has 99.9% support for Darkplaces mods and addons.
You can find this release in the downloads page (if it is not there, it is currently awaiting authorization.).