Windows Phone is an old operating system, formerly known as Windows Mobile or Pocket PC. Microsoft renamed its mobile operating system several times and none of the branding changes helped in the growth of Windows on Mobile. Microsoft launched Windows Mobile as PocketPC 2000, it was later renamed to Windows Phone as the company faced tough competition from rivals including Apple’s iOS and Google’s Android.
Microsoft deprecated Windows Mobile (6.5.5) and started to concentrate on Windows Phone. Windows Mobile 7 or Windows Phone 7 was announced back in 2010. Ballmer also admitted that Microsoft screwed up with Windows Mobile, the change in the OS name was expected to help the company but it didn’t.
In a partnership between Microsoft and Nokia, Windows Phone became the primary smartphone operating-system for Nokia. The first two phones from Nokia were the Lumia 800 and Lumia 710 with Windows Phone 7. Microsoft released Windows Phone 7.8 to older phones as the Windows Phone 7 could not be upgraded to Windows Phone 8 due to hardware limitation.
Microsoft later updated Windows Phone 8.0 to 8.1 and added some new features to the operating system. The company announced Windows 10 Mobile on January 21, 2015, and allowed only selected devices to upgrade to the new version. Microsoft released Windows 10 Mobile Threshold, Anniversary Update and Creators Update to selected phones.
You can watch the above video and go through the journey of Windows Phone and find how the OS evolved in past two decades.