An American soldier takes a selfie at the U.S. army base in Qayyara, south of Mosul October 25, 2016. REUTERS/Alaa Al-Marjani 

Recording artist Usher signs the back of an iPhone after unveiling his star on the Hollywood Walk of Fame in Los Angeles, California U.S., September 7, 2016. REUTERS/Mario Anzuoni 

Apple Inc. CEO Tim Cook shows dancer Maddie Ziegler an iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

The Apple iPhone 7 and AirPods are displayed during an Apple media event in San Francisco, California, U.S. September 7, 2016. Reuters/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the audio features of the iPhone 7 during a media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach TPX IMAGES OF THE DAY 

AirPods are displayed as Apple Inc CEO Tim Cook makes his closing remarks during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the pricing for the AirPods during an Apple media event in San Francisco, California, U.S. September 7, 2016. Reuters/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses Apple Pay during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the peformance of the iPhone 7 during a media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the Apple AirPods during a media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the depth of field and bokeh effects in the iPhone 7 Plus during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the redesigned home button on the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Phil Schiller, Senior Vice President of Worldwide Marketing at Apple Inc, discusses the redesigned home button on the iPhone 7 during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

Attendees use their iPhones during an Apple media event in San Francisco, California, U.S. September 7, 2016. REUTERS/Beck Diefenbach 

A man holds an iPhone 6 in a mobile phone shop in Moscow, Russia, September 26, 2014. REUTERS/Maxim Shemetov/File Photo 

People use iPhones at the film premiere of "Nine Lives" at the TCL Chinese theatre in Hollywood, California U.S., August 1, 2016. REUTERS/Mario Anzuoni 

A woman holds an iPhone displaying the TraffickCam app in this photo illustration in the Manhattan borough of New York, U.S., June 23, 2016. REUTERS/Sebastien Malo 

An Apple iPhone 6 with Apple Pay is shown in this photo illustration in Encinitas, California, U.S. June 3, 2015. REUTERS/Mike Blake/File Photo

Supporter Shawnee Badger, 22, waits for U.S. Democratic presidential candidate Bernie Sanders to speak at a campaign rally in Santa Barbara, California, U.S. May 28, 2016. REUTERS/Lucy Nicholson TPX IMAGES OF THE DAY

A guest uses her Iphone to take pictures on the red carpet as she arrives for the screening of the film "Money Monster" out of competition at the 69th Cannes Film Festival in Cannes, France, May 12, 2016.REUTERS/Regis Duvignau 

A guest uses her Iphone to take pictures on the red carpet as she arrives for the screening of the film "Money Monster" out of competition at the 69th Cannes Film Festival in Cannes, France, May 12, 2016. REUTERS/Regis Duvignau 

A guest uses her Iphone to take pictures on the red carpet as she arrives for the screening of the film "Money Monster" out of competition at the 69th Cannes Film Festival in Cannes, France, May 12, 2016. REUTERS/Regis Duvignau 

A guest uses her Iphone to take pictures on the red carpet as she arrives for the screening of the film "Money Monster" out of competition at the 69th Cannes Film Festival in Cannes, France, May 12, 2016. REUTERS/Regis Duvignau 

A guest uses her Iphone to take pictures on the red carpet as she arrives for the screening of the film "Money Monster" out of competition at the 69th Cannes Film Festival in Cannes, France, May 12, 2016. REUTERS/Regis Duvignau 

A combination pictures shows guests using their Iphone to take pictures on the red carpet as they arrive for the screening of the film "Money Monster" out of competition at the 69th Cannes Film Festival in Cannes, France, May 12, 2016. REUTERS/Regis Duvignau 

Co-founder of sweatcoin Oleg Fomenko holds an iPhone with the sweat coin app open, at his office in London, Britain May 4, 2016. REUTERS/Paul Hackett 

A woman holds her iPhone up to Republican U.S. presidential candidate Donald Trump at a campaign rally in Costa Mesa, California, U.S., April 28, 2016. REUTERS/Lucy Nicholson 

A woman speaks on her iPhone as she walks on a busy street in downtown Shanghai September 10, 2013. REUTERS/Aly Song/File Photo 

Formula One - Chinese F1 Grand Prix - Shanghai, China - 17/4/16 - Mercedes Formula One driver Lewis Hamilton of Britain before the Chinese Grand Prix. REUTERS/Aly Song TPX IMAGES OF THE DAY

Apple Vice President Greg Joswiak introduces the iPhone SE during an event at the Apple headquarters in Cupertino, California March 21, 2016. REUTERS/Stephen Lam TPX IMAGES OF THE DAY

Dutch far-right Party for Freedom (PVV) leader Geert Wilders takes a picture of the photographers prior to his trial in a courtroom of the courthouse in Schiphol, the Netherlands March 18, 2016. REUTERS/Michael Kooren 

Dutch far-right Party for Freedom (PVV) leader Geert Wilders shows the picture of the photographers he took with his cell phone prior to his trial in the courtroom in the courthouse in Schiphol, the Netherlands March 18, 2016. REUTERS/Michael Kooren TPX IMAGES OF THE DAY 

A woman takes a picture of a pedestrian traffic light with a female figure during International Women's Day in Valencia, Spain, March 8, 2016. REUTERS/Heino Kalis TPX IMAGES OF THE DAY

Formula One driver Lewis Hamilton takes a picture with his mobile phone as he attends designer Bill Gaytten's Fall/Winter 2016/2017 women's ready-to-wear collection for fashion house John Galliano in Paris, France, March 6, 2016. REUTERS/Gonzalo Fuentes 

Formula One driver Lewis Hamilton takes a picture with his mobile phone as he attends designer Bill Gaytten's Fall/Winter 2016/2017 women's ready-to-wear collection for fashion house John Galliano in Paris, France, March 6, 2016. REUTERS/Gonzalo Fuentes 

Formula One driver Lewis Hamilton takes a picture with his mobile phone as he attends designer Bill Gaytten's Fall/Winter 2016/2017 women's ready-to-wear collection for fashion house John Galliano in Paris, France, March 6, 2016. REUTERS/Gonzalo Fuentes 

Formula One driver Lewis Hamilton takes a picture with his mobile phone as he attends designer Bill Gaytten's Fall/Winter 2016/2017 women's ready-to-wear collection for fashion house John Galliano in Paris, France, March 6, 2016. REUTERS/Gonzalo Fuentes 

A man displays a protest message on his iPhone at a small rally in support of Apple's refusal to help the FBI access the cell phone of a gunman involved in the killings of 14 people in San Bernardino, in Santa Monica, California, United States, February 23, 2016. REUTERS/Lucy Nicholson 

A demonstrator holds a sign during a protest against the FBI's request to extract data from iPhones in cases across the country, outside the Apple Store in New York February 23, 2016. REUTERS/Shannon Stapleton TPX IMAGES OF THE DAY

An employee uses an Apple iPhone to demonstrate to reporters how to pay using the Apple Pay service at an Apple store in Beijing, China, February 17, 2016. REUTERS/Damir Sagolj 

Employees use an Apple iPhone to demonstrate to reporters how to pay using Apple Pay service at an Apple store in Beijing, China, February 17, 2016. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY

French photographer Brigitte Lacombe and member of the international jury for the 66th Berlinale International Film Festival takes photographs with an iPhone during a photocall in Berlin February 11, 2016. The festival runs from February 11 until February 21 in the German capital. REUTERS/Stefanie Loos

Australian Open winner Angelique Kerber of Germany uses her mobile phone to conduct a live television interview after her arrival at the airport in Frankfurt, Germany, early morning February 1, 2016. Kerber became the first German tennis player to win a Grand Slam tournament since Steffi Graf in 1999, by beating Serena Williams of the U.S. in the final of the Australian Open in Melbourne. REUTERS/Kai Pfaffenbach 

U.S. Republican presidential candidate Marco Rubio is photographed with supporters at a campaign rally in Raleigh, North Carolina January 9, 2016. Rubio is making a stop in the North Carolina capital ahead of the state's March 15 primary. REUTERS/Jonathan Drake 

iPhone cases are pictured on a wall Apple store in the Manhattan borough of New York December 9, 2015. REUTERS/Carlo Allegri 

A man wearing a mask takes a picture with his iPhone at the Tiananmen Square during a heavily polluted day in Beijing, China, November 29, 2015. Beijing plans to ramp up its already tough car emission standards by 2017 in a bid by one of the world's most polluted cities to improve its often hazardous air quality. REUTERS/Kim Kyung-Hoon 

A Tibetan Buddhist monk takes pictures with his smartphone of a daily chanting session at a Buddhist laymen lodge during the Utmost Bliss Dharma Assembly, the last of the four Dharma assemblies at Larung Wuming Buddhist Institute in remote Sertar county, Garze Tibetan Autonomous Prefecture, Sichuan province, China early October 30, 2015. The eight-day gathering of people chanting mantras and listening to teachings of monks starts every year around the 22nd of the ninth month on Tibetan calendar, the great day of Buddha's Descending from Tushita Heavens. The Larung Wuming Buddhist Institute, located some 3700 to 4000 metres above the sea level was founded in 1980 by Khenpo Jigme Phuntsok, an influential lama of Nyingma sect of Tibetan buddhism with only around 30 students but is now widely known as one of the biggest centres to study Tibetan Buddhism in the world. Picture taken October 30, 2015. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY

Toby Fulp, 38, holds an iPhone as he stands dressed as a character from the film "Back to the Future Part II" outside the Burger King featured in the movie, in Los Angeles, California, United States, October 21, 2015. Today marks the day that the movie's main character, Marty McFly, travelled to the future in the 1989 "Back to the Future" sequel. REUTERS/Lucy Nicholson 

Lucy Kelly is seen on a screen attached to a 'telepresence robot', which she used to purchase her iPhone 6s during the official launch at the Apple store in central Sydney, Australia, September 25, 2015. The new iPhone 6s and 6s Plus arrive in stores and at consumers' doorsteps on Friday, kicking off a sales cycle that will be scrutinized for signs of how much juice Apple's marquee product has left. Apple has a tough act to follow after the success of the iPhone 6, but sales are expected to benefit this year from the inclusion of the Chinese market, where the gadget's debut was delayed in 2014 due to regulatory issues. REUTERS/David Gray 

A customer holds an iPhone 6s during the official launch at the Apple store in central Sydney, Australia, September 25, 2015. The new iPhone 6s and 6s Plus arrive in stores and at consumers' doorsteps on Friday, kicking off a sales cycle that will be scrutinized for signs of how much juice Apple's marquee product has left. Apple has a tough act to follow after the success of the iPhone 6, but sales are expected to benefit this year from the inclusion of the Chinese market, where the gadget's debut was delayed in 2014 due to regulatory issues. REUTERS/David Gray TPX IMAGES OF THE DAY

People sleep as they queue overnight for the launch of the new Apple iPhone 6s mobile phone at a mall in Singapore September 25, 2015. REUTERS/Edgar Su

People rest as they queue overnight for the launch of the new Apple iPhone 6s mobile phone at a mall in Singapore September 25, 2015. REUTERS/Edgar Su

People sleep as they queue overnight for the launch of the new Apple iPhone 6s mobile phone at a mall in Singapore September 25, 2015. REUTERS/Edgar Su

People sleep as they queue overnight for the launch of the new Apple iPhone 6s mobile phone at a mall in Singapore September 25, 2015. REUTERS/Edgar Su