Which .NET version for C# 5 async features [closed]

Question

Which version of .NET does the user have to have installed on their computer for a developer to use the updated async functionality in C# 5?

Answer 1

C# Async features use classes introduced in .Net 4.5

However, you can also use the Async Targetting Pack from NuGet, which includes these classes for .Net 4.0.