DEV-TEAM is the name of a team that specializes in jailbreaking and software decompression of Apple iOS systems.
Apple iOS is an operating system for handheld devices developed by Apple. Apple first announced this system at the Macworld conference on January 9, 2007. It was originally designed for use with the iPhone, and was later applied to Apple products such as iPod touch, iPad, and Apple TV. iOS is the same as Apple's Mac OS X operating system. It is also based on Darwin, so it is also a Unix-like commercial operating system.
Originally this system was called iPhone OS, until it was announced at the WWDC conference on June 7, 2010 that it would be renamed iOS. As of November 2011, according to Canalys data, iOS has occupied 30% of the global smartphone system market share, and its market share in the United States is 43%.