Upgrading from .NET 3.5 to 4. Questions to think about?

Curious about things to consider to avoid any code breaks, etc to upgr开发者_StackOverflowade from .NET 3.5 to 4.

I am particularly interested in: - What would be the server requirements to deploy a .NET 4 app? Does it need any particular version of IIS and Windows Server to run?

I am facing serious performance issues with Entity Framework due to the large size of database and initialization takes long time for the first user to login. .NET 4 seems to realize this as a widespread issue and has something called PreWarm apps. Scottgu's post here seems to talk more about it. But, curious if this will work on IIS 6 and WinServer 2003.

Are there any other things i need to think of before making the switch to .NET 4?

.NET Framework 4 Beta 2 can be installed on Windows Server 2003. The software requirements are:

Supported Operating Systems: Windows Server 2003; Windows Server 2008; Windows Vista; Windows XP

.NET Framework 4 can be installed on the following operating systems:
- Windows XP SP3
- Windows Server 2003 SP2
- Windows Vista SP1
- Windows 7
- Windows Server 2008 (not supported on Server Core Role)
- Windows Server 2008 R2 (not supported on Server Core Role) Note that .NET Framework 4 is currently in Beta. If you have a working app on production, you might want to consider waiting for its RTM.