I have tried upgrading the hdp 2.6.2 cluster to 2.6.4 using the vdf file, but now i am unable to delet the 2.6.4 version from my list, 2.6.4 has been installed on some of my hosts but when i go to ambari version it is showing 2.6.2 as my current version.
"Only the versions that are not installed in a cluster can be de-registered." (if the version is fully or partially installed on nodes of cluster then "Deregister Version" option will be disabled.)
It is OK to have HDP 220.127.116.11-91 version registered it will be helpful when you would liek to upgrade your HDP.
There is no Harm in keeping few registered versions.
WE have tried to install hdp 2.6.4 (current version is hdp 2.6.2) but its not installed correctly due to some reasons, now we need to remove it completely and then reinstall again.