So here's the deal. We have installed the latest version (SP4) of Sitefinity 3.7 into the staging server (We're about to deploy wee!) and migrated our project. The project was made with SP1, everything works well. But since of course upgrades are vital, we decided to use the patch that can be downloaded from your site to upgrade our SP1 project to SP4.
After merging the files and careful edits to the web.config file, we reloaded the site and voila! Errors!
Here's the initial error about Telerik.Framework:
Server Error in '/' Application.
Description: An error occurred during the processing
of a configuration file required to service this request. Please review
the specific error details below and modify your configuration file
Parser Error Message: Could not load file or
assembly 'Telerik.Framework' or one of its dependencies. This assembly
is built by a runtime newer than the currently loaded runtime and cannot
Line 128: </eventMappings>
Line 129: <providers>
Line 130: <add name="Simple Web Event Provider" type="Telerik.Utilities.TextFileWebEventProvider,Telerik.Framework" logFileName="~/App_Data/sitefinity.log"/>
Line 131: <add name="Simple Web Buffered Event Provider" type="Telerik.Utilities.BufferedTextFileWebEventProvider,Telerik.Framework" bufferMode="Notification" logFileName="~/App_Data/sitefinity.log"/>
Line 132: <add name="Code Benchmark Provider" type="Telerik.Utilities.CodeBenchmarkTextFileProvider,Telerik.Framework" enabled="False" logFileName="~/App_Data/performance.log"/>
Thanks for your help as always. More power :)