During DC upgrade, I did uninstall and reinstall of the DC. DC appears to be upgraded to the right version. However the old version of DC was left in DC list as well. Since then the polling is not working even the DC status says collecting data with polled item number. See snapshot 1. The discovery can run successfully, however there is no new performance for any devices ever since upgrade. The status of the device shows as unknown. See snapshot 2. How can I get rid of this old version DC from the list or make the new version DC polling data?