article_snippet.sent: 1st generation: 3 April 2010 .
article_snippet.sent: 3rd generation: 16 March 2012 .
article_snippet.sent: 4th generation: 2 November 2012 .
article_snippet.sent: Mini 1st generation: 2 November 2012 .
article_snippet.sent: Air: 1 November 2013 .
article_snippet.sent: Mini 2: 12 November 2013 .
article_snippet.sent: Air 2: 22 October 2014 .
article_snippet.sent: Mini 3: 22 October 2014 .