include DTrace, Doors, Service Management Facility, Solaris Containers, Solaris Multiplexed I/O, Solaris Volume Manager, ZFS, and Solaris Trusted Extensions. Updates to Solaris versions are periodically issued. In the past, these were named after the month and year of their release, such as "Solaris 10 1/13"; as of Solaris 11, sequential update numbers are appended to the release name with a period, such as "Oracle Solaris 11.4". In ascending order, the following versions of Solaris have been released: A more comprehensive summary of some Solaris versions is also available. Solaris releases are also described in the Solaris 2 FAQ. Development release The underlying Solaris codebase has been under continuous development since work began in the late 1980s on what was eventually released as Solaris 2.0. Each version such as Solaris 10 is based on a snapshot of this development codebase, taken near the time of its release, which is then maintained as a derived project. Updates to that project are built and delivered several times a year until the next official release comes out. The Solaris version under development by Sun since the release of Solaris 10 in 2005, was codenamed Nevada, and is derived from what is now the OpenSolaris codebase. In 2003, an addition to the Solaris development process was initiated. Under the program name Software Express for Solaris (or just Solaris Express), a binary release based on the current development basis was made available for download on a monthly basis, allowing anyone to try out new features and test the quality and stability of the OS as it progressed to the release of the next official Solaris version. A later change to this program introduced a quarterly release model with support available, renamed Solaris Express Developer Edition (SXDE). In 2007, Sun announced Project Indiana with several goals, including providing an open source binary distribution of the OpenSolaris project, replacing SXDE. The first release of this distribution was OpenSolaris 2008.05. The Solaris Express Community Edition (SXCE) was intended specifically for OpenSolaris developers. It was updated every two weeks until it was discontinued in January 2010, with a recommendation that users migrate to the OpenSolaris distribution. Although the download license seen when downloading the image files indicates its use is limited to personal, educational and evaluation purposes, the license acceptance form displayed when the user actually installs from these images lists additional uses including commercial and production environments. SXCE releases