We use perl scripts to log into vCenter 5.5 with Single Sign On. However if I use the same script to point to our 6.0 or 6.5 vCenter it fails. I updated to the latest SDK and still the same. Powercli and pyvmoni just work
vminfo.pl --server myserver.internal --passthroughauth --passthroughauthpackage Kerberos
Our 5.5 vCenter was Windows and the newer ones are vcsa, in case that makes a difference.