Microsoft finally announces the exact date and time that Windows 8.1 and Windows RT 8.1 are set to hit the market: October 18th, 12:00am in New Zealand. That’s October 17th, 7:00pm in Manila. After which, a free update will begin rolling out worldwide via the Windows Store to consumers who currently own Windows 8 or RT devices. Windows 8.1 will also be available on retail and on new devices after the date of launch. 
Windows 8.1 starts rolling out October 17th (PH time)