Winver

 , short for Windows Version and internally called Version Reporter Applet, is a utility included in most versions of Microsoft Windows used to obtain information about the operating system version.

It was first introduced in Windows 3.0, where it was implemented as a simple message box with the Windows logo, major and minor version number, copyright notice and information about the currently active mode of operation. It was kept virtually unchanged throughout the classic Windows series, with Windows 3.1 only changing the logo, and Windows 95 reducing the version information to the operating system name.

On NT-based Windows versions, the utility was included since Windows NT 3.1, where it was implemented similarly to its 16-bit counterpart as a simple box with the Windows logo, version and build numbers and a copyright notice. However, starting with Windows NT 3.5, it merely calls the  API function to display a standard about box, which aside from the version and copyright notices also contained information about the computer and the registered owner. With the introduction of the timebomb during the development of Windows 2000, winver was updated to query information about the timebomb, and if present, display it in the about box.

Up until Windows 7, the dialog also contained information about the available amount of RAM. During the development of Windows 8, the window was modified to include a legal notice about the confidentiality of internal builds and the consequences of leaking them outside the company. The year was removed from the copyright notice in the Cobalt semester of Windows 10 development, a change that was also backported to Windows Server 2022, as well as the Windows 10 May 2020 Update onwards, starting with build 19041.899, 19042.899 and 19043.899.

On Windows versions that don't include a standalone  executable, such as Windows Server Core or Windows PE, the dialog can be invoked using the   command. However, when invoked this way, the dialog won't include timebomb information, as that functionality is exclusive to the applet. The dialog caption will show garbage when invoked this way due to the differences between the parameters expected by  and the actual signature of the function.

Launching Windows NT's Winver on Windows 9x (in this case Windows 95 RTM) will cause the About screen to show: Microsoft Windows NT (R) Windows 95 Copyright © 1981-1995 Microsoft Corp.