I looked at your issue and it is not as simple as it may look like. It happens because the SDK 1.5 has the support for SWIS v3 and without the version switch in connection string you are by default connecting to the SWIS v3 (also mentioned in the error message). If you want to use the new SDK for your current installation, you have to use the switch -V2.
It will look then (according to the used script):
$source = Connect-Swis -Credential $credential1 -Hostname $hostname1 -V2
After upgrade to the newer NCM (or installing NPM 10.3, SAM 5.2, etc.) you can then remove the switch to use SWIS v3