Hi Shivendra ,
We regret fort the inconvenience caused.
You can refer the single version in a project by setting the Syncfusion assemblies Specific Version and Copy Local as True in your project. Please refer the below screenshot.
Note: Syncfusion supports multiple version in GAC. So no need to delete another version assemblies in GAC.
Please make sure the following things before build your application.
1) Multiple versions of Syncfusion assemblies does not referred in your project.
2) Please delete bin and obj folders exist in the application directory.
Please let us know if you need any further assistance on this.
Regards,
Vadivel