Upgrading nopComm from 2.65 to 3.50

I've been contracted to upgrade my client's nopComm website from version 2.65 to 3.50. Not having much experience with nopComm I ran into some issues right away...












if I delete the files and install 2.7, copy over the images and config files, it does not work unless I remove the ShopAll theme folder. It gives me the following error:

Server Error in '/' Application.
Configuration Error
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 appropriately.

Parser Error Message: An error occurred creating the configuration section handler for system.web.webPages.razor/host: Could not load file or assembly 'System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

In a nutshell, do I need to upgrade the ShopAll theme to get this to work?

Hi,

You need to replace the theme with the newest version, which you could find in the theme package and run all the upgrade scripts from 2.65 to 3.50. 
Please have your client raise a ticket and we will send them in the ticket.