setup, handling suspend and resume, secure tunnelling over SSH, and printing and sound. Other display protocols NoMachine's NX protocol allow client connections to hosts via Remote Desktop Protocol (for Windows Remote Desktop Services sessions) and remote Virtual Network Computing sessions (most modern general-purpose operating system platforms), as well as XDM. NX derivatives and forks Prior to version 4.0, NoMachine released core NX technology under the GNU General Public License, and offered non-free commercial NX solutions, free client and server products for Linux and Solaris, and free client software for Microsoft Windows, macOS and embedded systems. Due to the free-software nature of older NX releases, the FreeNX project was started to provide wrapper scripts for the GPL NX libraries. FreeNX was developed and maintained by Fabian Franz, but has not announced a release since 2008. 2X Software has developed another commercial terminal server for Linux using the NX protocol. On July 7, 2009, Google announced their open-source NX server, Neatx, as an internal project. The project had no releases and is not actively developed. Its source code is available under the GNU GPL v2 license. X2Go is based on the 3.x NX libraries, but is not compatible with other implementations. The client and server are released under a combination of GNU GPLv2 or later, and GNU AGPLv3 or later. Clients The primary NX clients are the official freeware, NoMachine, and NoMachine Enterprise Client. Several open-source projects can also use the NX protocol but many of these OSS projects do not work with more recent versions of the official NX software. An OS mature project was Lawrence Roufail's nxc client library, a full library which can be used for other clients to build upon. The nxrun application utilizes this library. , the library does not allow suspending or resuming sessions, and uses only JPEG graphics compression. The kNX project was a proof-of-concept application written by Joseph Wenninger, with plans for it to eventually become a complete NX client to show that an open-source client could be written. Its development was halted before it was completed. In late 2005, Fabian Franz and George Wright began modifying kNX to use the nxc library, but abandoned the project. More recent open-source efforts include QtNX, which offers full suspend and resume. However, it has been reported as incompatible with the most recent NX libraries. Nxcl, an update to nxclientlib, the core of QtNX, was completed by