Complex sentence: On 26 June 2013 the Galaxy S4 LTE-A was released, this variant of the S4 is the world's first phone optimized to work on South Korea's LTE-A network.
Split into simpler sentences: On 26 June 2013 the Galaxy S4 LTE-A was released. This variant of the S4 is the world's first phone optimized to work on South Korea's LTE-A network.