Urban Armor Gear, the company that produced the case that secured the safe return of the iPhone, undertook the stunt.
The phone (within the UAG case) was attached to a weather balloon and sent up to heights of over 30,000 m. It experienced temperatures as low as -56 °C which caused it to shut down during the flight. On the edge of space the phone was released from the balloon and fell back to earth. It landed fully intact despite the cold temperatures and heavy landing.
Urban Armor Gear can now officially say their products are tested from space! I wonder if this will become a regular occurrence for products in the future.