Going Back from .NET 4 to 3.5

Problem:

I have built my website in VS2010, i have uploaded to my host, but it won’t work. they say they don’t support . NET 4 yet.

Solution:

On your project properties there is a Framework Target option. Select 3.5 and compile. then uploaded it again and it should work

Concerns:

You might have used some specific . NET 4 Feature, in that case you will have to replace it with a 3.5 one.