What versions of Windows will .Net 4.0 support?

What versions of Wi开发者_StackOverflowndows is Microsoft planning to support with .NET 4.0?

The official list is here.

Supported operating systems are:

• Windows XP (SP3)
• Windows Vista (SP1)
• Windows 7
• Windows Server 2003 (Base & R2)
• Windows Server 2008 (Base & R2, all editions, not supported in Server Core Role)
• Windows Small Business Server 2003 & 2008

Notable operating systems not supported include XP Media centre edition, XP Tablet PC edition and Windows 2000.

(The .NET Framework Client Profile is not supported on IA-64 systems.)

[Updated list for final release]

(see here (beta 1)) (see here (beta 2))

According to the .NET 4.0 Beta 2 download page, it's supported on Windows Server 2003, Windows Server 2008, Windows Vista and Windows XP.

Historically, new releases of .net are supported with all operating systems currently supported by Microsoft. For example, .Net 2.0 base supports Windows 98. But Windows 98 end-of-life'd in 2006 and when .Net 2.0 sp1 came out in 2007 support for Windows 98 was dropped, even though it would probably work just fine.

That means .Net 4.0 is likely to be supported on XP sp2 and newer (and not base XP or XP sp1, which have both end-of-life'd) even though it would probably work just fine on older XP releases.

The big question is service pack 2 and whether they find a delay-worthy bug in .Net 4. Service Pack 2 reaches end-of-life on July 13, 2010. If they have to delay .Net 4 even a few months, I'll give good odds that it won't support XP sp2. But if it makes it's release schedule it likely will support XP sp2.