Solution:
It appears that older versions of DevExpress assemblies have been cached and now they conflict with the newly installed assemblies. Please follow these steps, which should help you overcome the problem:
1. Close VS.
2. Restart your IIS or better yet, restart the "World Wide Web Publishing" service (Start menu\Settings\Control Panel\Administrative tools\Services).
3. Clear the "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\" and "C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\" folders.
4. Clear the project's Bin and Obj folders.
5. Rebuild your application.
Please refer to : https://www.devexpress.com/Support/Center/Question/Details/Q348002
