The US Department of Defense has signed a $927m, five-year deal for Microsoft's enterprise technical support services.
Under the contract with the Defense Information Systems Agency (DISA), Microsoft will provide consulting services that include software developers and product teams "to leverage a variety of proprietary resources and source code" and Microsoft premier support services, such as tools and knowledge bases, problem resolution assistance from product developers.
The DoD contract statement also said the deal would include "access to Microsoft source code when applicable to support Department of Defense's mission".
The support will mostly take place in the US, but the DoD said support services may also be required at multiple locations outside the continental US.
In January 2016, the DoD announced plans to migrate four million devices to Windows 10 by January 2017, although rollout in some military organizations may take a year longer. The DoD said the move would improve its "cybersecurity posture, lower the cost of IT and streamline the IT operating environment".
DISA is a combat support agency of DoD with 6,000 civilian employees, 1,500 active duty military personnel from the Army, Air Force, Navy, and Marine Corps, and approximately 7,500 defense contractors. The agency provides and operates command and control and enterprise information systems.
Update 22 December: Microsoft has now said that the deal does not include access to its source code.
A DISA spokesperson confirmed: "The Department of Defense does not, and will not, have access to Microsoft's proprietary source codes. The METSS-II contract is a sole-source follow-on contract to continue and leverage Microsoft support services." The contract is for Microsoft support services performed by Microsoft "blue badge" employees.
However, government customers are able to review Microsoft's source code at a number of 'Transparency Centres' around the world in order to confirm that there are no 'back doors' built into the software. The first of these opened in Redmond in 2014.