This is the complete script
#Variable of date type which is 3 days before the current date
$3days = (get-date).adddays(-3)
#Get list of all snapshots older than 3 days and delete them
Get-Navol | Get-NaSnapshot | where-object {$_.name -like "smo_*" -and $_.created -lt $3days} | Remove-NaSnapshot -Confirm
It was working properly until the upgrade.
Thanks