Microsoft has codenamed the next wave of major Windows releases "Threshold", and plans to deliver the updates in Autumn (in the southern hemisphere) 2015.
The leak comes via renowned Windows-watcher Mary Jo Foley, whose Microsoft sources tell her that the Threshold codename was used in a recent internal email from the company's operating systems chief Terry Myerson.
According to Foley, Threshold doesn't relate to a single, unified Windows OS, nor even the predicted merger of Windows Phone and Windows RT, which Microsoft hinted at last week. Instead, it will merely "add another level of commonality across Microsoft's various Windows-based platforms".
Microsoft has publicly stated that it aims to merge its various stores across desktop and mobile platforms. It's also working on making the developer toolsets for its various operating systems more similar.
Users won't have to wait until the year after next for an update to Windows, however. Windows 8.1 Update 1 will apparently drop with Windows Phone 8.1 in early 2014, although it's unlikely to contain any major changes to the Windows OS.