The Windows Insider program by Microsoft allows users who own a valid Windows 10 license to sign up for early builds of the operating system previously only accessible to developers. It was announced on September 30, 2014 along with Windows 10. By September 2015 over 7 million people took part in the Windows Insider Program. On February 12, 2015, Microsoft started to test out previews of Windows 10 Mobile. Microsoft announced that the Windows Insider program would continue beyond the official release of Windows 10 for future updates. Dona Sarkar is the head of the Windows Insider program. Similar to the Windows Insider program, both the Microsoft Office and Microsoft Bing teams have set up their own Insider program.