After Julie Larson Green let slip that three OSes are a bit too much last week, we are now hearing that Microsoft may be about to bring its various platforms under one umbrella. This goes beyond the much-rumoured unification of Windows RT and Windows Phone 8.

Codenamed Threshold, word of this 2015 release comes from ZDNet’s Mary Jo Foley, who has a stellar record when it comes to getting information on forthcoming Microsoft plans (She was also teased by Microsoft execs on stage during the recent Surface launch for her knack of getting stories early).

According to the report, Microsoft Executive VP Terry Myerson mentioned Threshold in an internal email about plans for his unified operating-system engineering group. Threshold will reportedly update all three major OS platforms (Xbox One, Windows and Windows Phone) to bring them even closer in terms of app development, deployment and maintenance.

Interestingly, Microsoft has once again looked to its creation Halo, launched back in 2001, for the codename. Threshold, is the planet around which the first halo ring orbited in the game. Earlier we had heard about Microsoft choosing the name Cortana for its Siri-like voice recognition software, which is expected to come to the major platforms soon.

The three OSes already share a Windows NT foundation and Threshold could end up merging their respective app stores, making it easier to own and develop apps. Reportedly, Microsoft is working towards making the developer tools as similar as possible for all three.