Microsoft is now believed to be preparing a 'technology preview' of its Windows 8 successor that will be available by late September or early October according to ZDNet.
The next operating system is codenamed 'Threshold' internally by Microsoft and is expected to be released to the public by mid-2015.
Leaks have suggested 'Threshold' will feature the return of the Start Menu, the Siri-like Cortana personal assistant, a greater focus on the desktop environment and elimination of the 'Charms bar'.
Windows 9 may also bring the unified operating system new CEO Satya Nadella has previously envisioned, potentially having Windows, Phone, Server and Xbox under the same release. It is unknown whether this will prompt Microsoft to change the Windows naming format after 7, 8 and 8.1.
The release of the finalised software is expected to come quicker than the Windows 8 roadmap as Microsoft pushes a fast cycle between major releases.
It's still unclear whether the Windows 9 Preview will only be available to developers but one unnamed reliable source claims it will be available to the public as well.