Microsoft is currently testing near-final versions of Windows 8.1, but the company won't release the final update publicly until October. According to sources familiar with Microsoft's plans, the software maker will finalize, or Release to Manufacturing (RTM), Windows 8.1, but the update will not be pushed out to existing machines until October. Partners and PC makers will receive the final bits later this month, and the gap until an October release will allow them to finalize their own testing and drivers for the roll out.

We're told that the Windows 8.1 update will be made available in October alongside new hardware from partners, including 7- and 8-inch devices. ZDNet's Mary Jo Foley originally reported details on the Windows 8.1 timing on Monday, and our own sources have confirmed that the gap from RTM to release will also allow Microsoft to continue supplying fixes and patches ready for the General Availability in October.

Near-final Windows 8.1 build leaks online

Windows 8.1 includes a number of multitasking improvements, new smaller Live Tiles, and a built-in Bing-powered search engine. A near-final version of the update leaked to the internet recently, offering a closer look at the changes between Preview and RTM. Microsoft is adding in a number of tutorials and Windows Phone-like menus to ease complaints over the usability of the operating system. The Windows 8.1 update will be made available around 12 months after Windows 8 first debuted in October last year.