If I have .NET Framework 2.0 and .NET Framework 3.5, do I need .NET Framework 3?

Question

Say I have .NET Framework 2.0, 3.0, 3.5 installed for an Asp.NET web application.

I realize that Framework 3.0 and 3.5 are just extensions to Framework 2, what is less clear is how 3.0 and 3.5 interrelate.

Am I safe uninstalling Framework 3 if the Asp.NET application targets 3.5?

Answer 1

.Net 3.0 introduced WCF, WPF and WF, extra libraries really working on top of the 2.0 runtime.

.Net 3.5 introduced upgrades to these libraries and comes with support for Linq (new language features).

You can safely uninstall 3.0, and replace it with 3.5, as 3.5 covers the libraries introduced in 3.0. Check out this page at wikipedia for more information on the versions and what they bring to the table.

When you install 3.5 you will get a 3.0 folder in your framework folder (along with all other versions).

Answer 2

Those three versions share the same CLR version (2.0) and each new version just adds new features not available in the previous version. This basically means 3.0 depends on 2.0 and 3.5 depends on 3.0 and 2.0 so uninstalling 3.0 is not possible unless you also uninstall 3.5.

For detailed information about .NET Framework version you can check out:

.NET Framework Versions and Dependencies

Answer 3

Yes. But, as a rule, the framework is designed to support having multiple versions installed simultaneously. I'd leave it be unless space is a real issue.