 The client engine however, remains unchanged as Azureus.Up to version 2.5.0.4, Azureus was distributed under the GNU General Public License (GPL); beginning with the version 3 distribution, the license presented upon installation changed.While it still states that the "Azureus Application" is available under the GPL, completing installation requires the user to agree to the terms of the "Vuze Platform," which include restrictions on use, reverse-engineering, and sublicensing.