How do I fix the “compilerVersion” IIS error?

Question

I\'m getting this exception:

System.Configuration.ConfigurationErrorsException: The value for the \'compilerVersion\' attribute in the provider opti

Answer 1

In my case, I am using an old Webform website (V 2.0), need to append a new application which is developed in MVC4.0. This same error I was facing and after many permutations and combination of the given solution, I wrapped the whole web.comfig of the parent application in the following tag

...... web config tags here........