.net 3.5 and .net 4.0

Hi Akshay,

There are some articles related to your query. You can look into this.

http://dotnetguts.blogspot.com/2010/06/difference-between-net-40-and-net-35-20.html
http://www.dotnetfunda.com/forums/thread5802-difference-between-35-and-40.aspx
http://www.daniweb.com/web-development/aspnet/threads/346530/what-is-the-difference-between-.net-1.12.03.03.5-and-4.0-

As it's a Windows Forms application it doesn't really matter which version you use as there have been no changes to that particular platform.

However, if you have a choice, then I'd use .NET 4.0 rather than .NET 3.5 as there have been some useful additions to the C#  language itself.

Hi, 

This link is very useful but I'm still not sure if I should use .NET 3.5 or 4.0. I'm working on a project to create a Windows Form Softphone with this sample program  http://www.voip-sip-sdk.com/p_136-windows-form-c-sip-softphone-voip.html. I need an advice which development environment I should use for my project.
Thanks for your help in advance!

Tim

Here's the official summary with links for more info on individual new features:

http://msdn.microsoft.com/en-us/library/ms171868.aspx