Bulk rename/append name of devices

OK...

Doing a get on the device got me a list of systemproperties that had the type listed in the returned JSON object.

With that information, this works for the name and the hostname, but not the displayname:

# Change Properties
# Construct URL
$resourcePath   = "/device/devices/2332"
$url            = $URLRoot + $resourcePath

# Construct Data Body
$data = `
@"
{
    `"name`" : `"Server Name`",
    `"systemProperties`" : [
        {
            `"type`"  : `"system`"             ,
            `"name`"  : `"system.displayname`" ,
            `"value`" : `"Server Name`"
        }, {
            `"type`"  : `"system`"             ,
            `"name`"  : `"system.hostname`"    ,
            `"value`" : `"Server Name`"
        }
    ]
}
"@

write-output "Making Request: `n $data"

$response       = Send-Request   `
    -accesskey    $accessKey     `
    -accessid     $accessId      `
    -URL          $url           `
    -data         $data          `
    -httpVerb     "PATCH"

write-output "response: `n $response"

Why is system.displayname different than all of the other properties?