An anonymous reader writes: A file named "UpgradeSubscription.exe" is found buried in the System32 folder of Windows 10 build 14376, alongside 590 other .exe files. ZDNet reports the file has been part of other recent preview builds, but just recently uncovered. "In the file's properties, it's described as the Windows Upgrade to Subscription Tool, and its date and time stamp corresponds to other administrative tools in the same build," reports ZDNet. You can view the screenshot here. Microsoft responded to ZDNet saying: "The Windows Upgrade to Subscription tool, found in the latest Windows Insider builds, helps to manage certain volume licensing upgrades from Windows 10 Pro Anniversary Update to Windows 10 Enterprise. This binary file is not associated with the free consumer upgrade offering nor is it applicable to consumer Windows editions." When pressed for additional details, Microsoft responded with, "No further comment." While the file does nothing, it does appear to confirm that it's related to licensing, referencing a registry value called AllowWindowsSubscription. Build 14376 reveals a few references to servicing packages named Microsoft-Client-License-Platform-Upgrade-Subscription-Package. Last year, there was some talk about Windows 10 being the last version of Windows as Microsoft is pushing a "Windows as a service" vision. When news broke in April about Windows Phone's sharp revenue declines, PCWorld reported that CEO Satya Nadella's strategy is to grow Microsoft's revenues by convincing customers to adopt its paid subscription services.