Overview
The primary focus of Microsoft .NET Framework 1.1 Service Pack 1 (SP1) is improved security. In addition, the service pack includes roll-ups of all reported customer issues found after the release of the Microsoft .NET Framework 1.1. Of particular note, SP1 provides better support for consuming WSDL documents, Data Execution prevention and protection from security issues such as buffer overruns.

SP1 also provides support for Windows XP Service Pack 2 to provide a safer, more reliable experience for customers using Windows XP.

SP1 is available in 22 languages.

System Requirements
Supported Operating Systems: TabletPC; Windows 2000; Windows 2000 Advanced Server; Windows 2000 Professional Edition ; Windows 2000 Server; Windows 2000 Service Pack 2; Windows 2000 Service Pack 3; Windows 2000 Service Pack 4; Windows 98; Windows 98 Second Edition; Windows ME; Windows NT; Windows Server 2003 Service Pack 1 for Itanium-based Systems; Windows Server 2003 x64 editions; Windows Server 2003, Datacenter Edition for 64-Bit Itanium-Based Systems; Windows Server 2003, Datacenter x64 Edition; Windows Server 2003, Enterprise Edition for Itanium-based Systems; Windows Server 2003, Enterprise x64 Edition; Windows Server 2003, Standard x64 Edition; Windows Vista Business; Windows Vista Business 64-bit edition; Windows Vista Enterprise; Windows Vista Enterprise 64-bit edition; Windows Vista Home Basic; Windows Vista Home Basic 64-bit edition; Windows Vista Home Premium; Windows Vista Home Premium 64-bit edition; Windows Vista Starter; Windows Vista Ultimate; Windows Vista Ultimate 64-bit edition; Windows XP; Windows XP Home Edition ; Windows XP Media Center Edition; Windows XP Professional Edition ; Windows XP Professional x64 Edition ; Windows XP Service Pack 1; Windows XP Service Pack 2
Software Requirements:

Microsoft Internet Explorer 5.01 or later (install Internet Explorer 6.0).