Would it be possible for you to follow the steps below:
1. Copy all dlls from the Empty folder of the Sitefinity 6.0 project.
2. Then replace the old dlls in the bin folder of your Sitefinity 5.4 project.
3. Open the project in Visual Studio.
4. Removed all Telerik references and added the new ones from the bin folder of your project.
All the best,
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items