Upgrading Sitefinity v. 3.7 to .Net Framework v. 4.0

Sitefinity v. 3.7 was recently updated to support Microsoft.Net Framework v. 4.0 with the release of SP4.  If you currently host your ASP.Net Web Sites on shared hosting providers such as Discount ASP.Net or GoDaddy.com, you will probably want to update your version of Sitefinity for .Net Framework v. 4.0 support so that it works properly on these hosted platforms.

In order to do this, there are several steps that you must follow:

1. Make sure that your local development workstation or hosting provider has .Net Framework v. 4.0 installed/supported
2. From the Sitefinity.com website, download the Sitefinity v. 3.7 SP4 patch for .Net Framework v. 4.0 called Sitefinity_3_7_2136_standard_NET40_patch.zip
3. Prior to performing the update, make sure that you back up your current v. 3.7 website and web.config file.
4. Now, extract the contents of the .zip file that contains the patch
5. Copy the contents of the .zip file over the existing directories in the v. 3.7 website
6. Using a comparison tool such as Beyond Compare, compare the contents of the new_web.config with the existing web.config
7. Make sure that any customizations in the old web.config are applied to the new_web.config
8. Save the changes to the new_web.config file
9. Rename the old web.config file to web.config.bak
10. Rename the new_web.config to web.config
11. Now, if you are running on a platform such as Windows Server 2008 or Windows Server 2008 R2, you will need to change the currently running Application Pool assigned to the website/virtual directory.  
12. The appropriate Application Pools for the .Net Framework v. 4.0 are ASP.NET v4.0 and ASP.NET v4.0 Classic
13. Depending on your requirements you will either use one of these existing Application Pools or else you will create a new Application Pool to assign to the website/virtual directory
14. In the Application Pool settings, make sure you assign the appropriate user identity.  For example, by default, ApplicationPoolIdentity is used for Windows Server 2008 R2.  However, this privilege is unhandled by most applications including Sitefinity.  Therefore, you will have to switch it to another account such as NetworkService
15. Now load your upgraded Sitefinity v. 3.7 website and verify that it is correctly running under .Net 4.0
16. If it works without any error messages, you have succeeded in getting your Sitefinity v. 3.7 website to run under .Net 4.0!