OpenWindows 1.0 was released in 1989 as a separately licensed addition to SunOS 4.0, replacing the older SunView (originally "SunTools") windowing system. Its core is the "xnews server", a hybrid window server that as its name implies supports both X11 and NeWS-based applications. The server can also display legacy SunView applications, although this functionality was not well-supported. (A standalone NeWS windowing system was also available for a time, but was never the primary SunOS windowing environment.) Starting with SunOS 4.1.1 in 1990, OpenWindows 2.0 was bundled with the operating system.