In Short

iOS 5, code-named Telluride, was introduced by Apple during the WWDC 2011 keynote on June 6 and shipped on October 21. Tentpole features included Notification Center, Newsstand, Reminders, iMessage, Siri, integration with iCloud, and more. iOS 5.1, code-named Hoodoo, was released on March 7, 2012. The last version, iOS 5.1.1 was released on May 7, 2012.