IMPORTANT NOTICE: All SP4 users running SP4 v3.1a or earlier must delete this registry key to receive the latest WU updates: Version History for Windows XP Service Pack 4 Unofficial: Microsoft Windows XP Service Pack 3 Offical can be downloaded here. These security enhancements address issues not fixed by Microsoft updates. Windows XP SP4 security enhancements: Windows XP SP4 includes registry updates to enhance security provided by Stefan Kanthak, a security expert. If you download the you can also scan Windows Update for POSReady updates because the POSReady trick has been included. NET Framework 1.1 will always be installed if Media Center Edition is present. Only Microsoft.NET Framework 3.5 is enabled by default in an integrated installation. NET 1.x, 3.5 versions are automatically installed/updated in live installations. NET Framework 1.1, 3.5 and 4.0 until January 2016 have been included. Currently, Microsoft.NET Frameworks 4.0, 3.5, 1.1 and 1.0 (Tablet PC only) are included in the Windows XP SP4 package. Request-only hotfixes have been included. It includes updates for most Windows XP components, including MCE and Tablet PC. It can be applied to a live Windows XP system which has SP1, at the minimum, installed or it can be slipstreamed (integrated) in any Windows XP installation media.

3.1b is expected to be the final release. Windows XP Service Pack 4 Unofficial is a cumulative update rollup for Windows XP (x86) English as well as security enhancements not addressed by Microsoft.

Windows xp service pack 1