Can I run ASP.NET 2.0 and 3.5 code on the same website?

Can I run ASP.NET 2.0 and 3.5 code on the same website? ...or, do I need to separate them by applications, and/or servers?

From stackoverflow Jason

• Yes you can without issue.

  From Mitchel Sellers

• As long as your server is running 3.5, you can run both.

  From James Hall

• .Net 3.5 is an extenion to the .Net 2.0 framework. After you upgrade to the .Net 3.5 framework you can run applications that use all of the .Net 2.0/3.0 and 3.5 framworks.

  From $pageUsers[$post.author].name

• .NET 3.5 is 2.0 with a few extra libraries. So the answer is yes you can run them on the same web site. In fact you cannot even set a web application to run under 3.5. It just runs under 2.0. You can check the ASP.NET tab in the properties of an IIS site to see that there isn't even an option to run your application under 3.5.

  From Erikk Ross

• You can run code in .NET 2.0 and .NET 3.5 on the same server, but you must have at least one application pool per framework version. The only thing you have to watch is not to mix a 2.0 app and a 3.5 app in the same pool.

  Rationale : only one framework can be loaded for each process and each application spawns its own process(es)

  Herb Caudill : This is incorrect - you can't mix 1.1 and 2.0 sites in an app pool, but as far as IIS is concerned 2.0 and 3.5 are the same.
  From Johan Buret

• You can run them both at the same time as long as .NET 3.5 is installed.

  From Joseph Daigle

• As far as IIS is concerned, 3.5 and 2.0 are the same. What you have to be careful about is not mixing 1.1 and 2.0 in the same app pool.

  From Herb Caudill

• I would just convert all of the code to 3.5, and it should work perfectly, if you have 3.5 installed on the box.

  Aslo note that VS 2008 does multi targeting, and a lot of the features that are new in 3.5 are actually features of the compiler, not the framework itself. So you can target the 2.0 framework and still get many of the new featres of 3.5.

  From Charles Graham

• ASP.NET 3.5 is still running on the .NET 2.0 CLR, if you go into IIS you'll see that you can only pick 2.0 or 1.1

  So the answer is, yes...ASP.NET 3.5 is basically just extra assemblies in the GAC.

  .NET 3.5 was just modifications to the compilers themselves, and the libraries, not the CLR.

  From FlySwat