Each new Infragistics release requires Kevin to release new sets of controls as the DLL references are different. If you are working with existing projects, make sure you use Infragistics Upgrade Projects tool in order to get the components upgraded within your project.

I have not had much success with the upgrades so here are steps I follow:

Infragistics Upgrade Steps (that I take ... your mileage may vary)
1. Uninstall the old Infragistics version
2. Install the new Infragistics version.
3. Install Kevin's latest MM.NET Infragistics controls (matching the newly installed version).
4. Reboot PC
5. Run the Infragistics Upgrade Projects tool (if you want existing projects upgraded - this changes the references within the projects to use the latest dll versions)

Hope this helps all fellow Infragistics control and MM.NET users!
Please respond with any other steps that work well for you when performing these upgrades.