Complex sentence: The S7 series is a successor to the 2015 Galaxy S6, S6 Edge and S6 Edge +, and was officially unveiled on 21 February 2016, during a Samsung press conference at Mobile World Congress, with a European and North American release on 11 March 2016.
Split into simpler sentences: The S7 series serves as the successor to the Galaxy S6, S6 Edge and S6 Edge + released in 2015. The phones were officially unveiled on 21 February 2016, during a Samsung press conference at Mobile World Congress, with a European and North American release on 11 March 2016.