Complex sentence: The iPhone 6 and 6 Plus were discontinued on September 7,2016 when Apple released the iPhone 7 and iPhone 7 Plus, and their spot as the entry-level iPhone has been taken by the iPhone SE that was released earlier on March 31,2016.
Split into simpler sentences: The iPhone 6 and 6 Plus were discontinued on September 7,2016 when Apple announced the iPhone 7 and iPhone 7 Plus. Their spot as the entry-level iPhone has been taken by the iPhone SE, which was released earlier on March 31,2016.