FAQ
What does Legacy Update run on?
| Operating System | Compatibility | |
|---|---|---|
| Windows 2000 Professional Windows 2000 Server | Supported on any edition of Windows 2000. Requires SP3 or SP4 and Internet Explorer 6. Legacy Update will install these for you automatically if needed. Known issues: After Legacy Update setup is completed, you may be returned to a Log On to Windows dialog with no username filled in. Simply log in as your user to proceed. |
| Windows XP Windows XP Embedded Windows Fundamentals for Legacy PCs Windows Embedded 2009 Windows Server 2003 Windows Server 2003 R2 Windows Home Server 2007 | Supported on any edition and service pack of Windows XP, Server 2003, and Embedded 2009. You can optionally upgrade to SP3 via Legacy Update setup. Includes Itanium editions. Known issues: You may need to use a workaround to start Legacy Update setup, due to a bug in Windows XP/Server 2003. On Windows Server 2003/2003 R2, checking for updates for the first time may take up to 30 minutes. Please be patient for this to complete. |
| Windows Vista Windows Server 2008 | Supported on any edition of Windows Vista or Server 2008 with SP2 and a certain set of required updates. Legacy Update will install these for you automatically if needed. You can also optionally install Internet Explorer 9. Includes Itanium editions. Known issues: Checking for updates for the first time may take up to 30 minutes. Please be patient for this to complete. |
| Windows 7 Windows Embedded 7 Windows Thin PC Windows Server 2008 R2 Windows Home Server 2011 | Supported on any edition of Windows 7 or Server 2008 R2 with SP1 and a certain set of required updates. Legacy Update will install these for you automatically if needed. |
| Windows 8 Windows 8.1 Windows Embedded 8 Windows Embedded 8.1 Windows Server 2012 Windows Server 2012 R2 | Supported on any edition of Windows 8/8.1 and Server 2012/2012 R2 with a certain set of required updates. Legacy Update will install these for you automatically if needed. Upgrading from Windows 8 to Windows 8.1 is recommended. This requires some manual steps - Legacy Update can’t do this for you. Not supported on Windows 8/8.1 RT (ARM) devices due to the strict code signing requirements of this version of Windows 8/8.1. |
| Windows 10 Windows 11 Windows Server 2016, 2019, 2022 Windows Server 2025 | Supported on any edition of Windows 10/11 and Server editions based on it, including Windows Insider preview builds. Legacy Update will only function as an alternative user interface you can access the Windows Update service, and won’t otherwise make changes to your system. Accessible via Microsoft Edge in Internet Explorer mode, or you can open Legacy Update in Internet Explorer through the Start menu shortcut. |
| Windows 95, 98, Me Windows NT 3.x/4.x | Earlier versions of Windows are currently not supported by Legacy Update. Try Windows Update Restored instead, another community project that aims to provide updates for earlier versions of the Windows Update service. |
| Windows CE Windows Mobile Windows Phone | Mobile editions such as Windows CE and Windows Phone are currently not supported by Legacy Update. They may work if manually configured to check for updates from Legacy Update’s proxy server, but are not officially supported. |
Legacy Update runs on 32-bit (x86), 64-bit (x86_64 or x64), and Itanium (IA64) editions of the above operating systems.
Legacy Update does not officially provide support for beta/unreleased versions of Windows. They may receive some updates, but most were removed a long time ago, or will not be suitable for the build you’re running.
Why doesn’t Legacy Update work on Windows 95, 98, Me, and NT 4?
Legacy Update works because we’re lucky enough that the Windows Update v6 protocol is pretty much the same today as it was when it was first released. As such, it simply proxies all protocol traffic to Microsoft’s official Windows Update servers. It seems unlikely that Microsoft will completely discontinue Windows Update for 2000/XP.
Windows 95, 98, Me, and NT 4 used Windows Update v3, with Windows Update v4 later coming to Windows 98, Me, and NT 4, in addition to the initial releases of Windows 2000 and XP. (v5 existed for a brief period before v6, but they are almost identical.) Both versions are now discontinued, making a reimplementation of them more difficult. In the case of v3, there are many catalog files and executables that need to be appropriately recovered from archives of the Windows Update service. In the case of v4, in addition to update executables needing to be recovered, a database also needs to be rebuilt.
I’m looking into making use of Windows Update v4 to provide a happy medium between Windows Update v3 and v6. It’s a bit more robust than v3 in a few ways, and isn’t an overly complicated protocol like v6. While v4 never officially supported Windows 95, I believe it should be possible to make it work there anyway (it will require Internet Explorer 5 to be installed first).
You can try the unrelated Windows Update Restored project, based on a revival of the Windows Update v3 and v4 services.