The New York City Police Department is upgrading to the iPhone.

The agency confirmed Tuesday it will replace 36,000 Windows Phones secured as part of a Mobility Initiative with Apple's iPhones.

The NYPD says the new iPhones will start rolling out this fall.

Jessica Tisch, the NYPD's deputy commissioner of information and technology, said the decision was made three years ago to use Windows Phones because neither iOS nor Google's Android allowed the department to "cost-effectively utilize prior investment in custom Windows applications."

"A year ago, we learned that improvements in Apple controls would allow NYPD to responsibly and cost effectively move our mobility initiative to the Apple platform," said Tisch.

Microsoft had previously closed off access to its suite of software including Office to only Windows-enabled devices. The company has changed its thinking since the arrival of CEO Satya Nadella, introducing apps in 2014 for software such as Word and Excel on Apple devices.

Details of the switch were first reported by The New York Post.

The smartphones were part of a $160 million Mobility Initiative unveiled in 2014 to help streamline law enforcement efforts by providing officers with access to tablets and mobile devices.

"The smartphones have made our cops smarter, faster, and more agile in their response to 911 calls, with response times down more than 8 percent," said Tisch.

Microsoft launched the Windows Phone platform as a potential competitor to iOS and Android, scooping up Nokia's handset business in 2013 for $9 billion. The acquisition was a disaster, forcing Microsoft to cut jobs and write down more than $7 billion.

Earlier this year, Microsoft confirmed it would no longer offer support for Windows Phone 8.1, the latest version of the mobile operating system.

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