I was looking at a way to compare versions of VDAs installed on various systems to see what systems needed to be updated. I ran into some issues trying to compare the versions as there are different formats and there was not a consistent numbering system going back to 7.15 that I could discern. So with some assistance from https://www.linkedin.com/in/douglas-ruehrwein-56835869/, I was able to get the version check working correctly. This ended up comparing to the target version and returning anything that was less than the target version. I didn’t want to target anything newer than the target as I had reasons for those particular systems to be running a newer VDA. You can combine this with the VDA upgrade script to output the DNSNames of the machines to upgrades machines outside of the target version.

This was first attempt and realized some machines didn’t show HostedMachineName.
This was the second attempt and got it to show the DNSName as well and this helped identify the Linux VDA machines.
Final using [System.Version] to compare the versioning numbers. This was the expected output.
# Script to get VDA versions below target version. This was done in PowerShell ISE 5.1 against 1912LTSRCU5 DDCs.
$adminAddress = "deliverycontroller.fqdn"
$date = Get-Date -Format MMddyyyy
$outputName = "VDAToUpgrade"
$report = @()
[System.Version]$targetVersion = "1912.0.5000.5174"
$getMachines = Get-BrokerMachine -AdminAddress $adminAddress -MaxRecordCount 1000000

foreach($machine in $getMachines){
  $line                   = "" | Select HostedMachineName, DNSName, AgentVersion, WillBeUpgraded
  $testVersion            = $machine.AgentVersion
  $line.HostedMachineName = $machine.HostedMachineName
  $line.DNSName           = $machine.DNSName
  $line.AgentVersion      = $machine.AgentVersion
  if([System.Version]$testVersion -ge [System.Version]($targetVersion)){

    $line.WillBeUpgraded  = "Current Version Or Newer"
  if([System.Version]$testVersion -lt [System.Version]($targetVersion)){

    $line.WillBeUpgraded  = "Yes"
  $report += $line

$report | Export-Csv -Path c:\scripts\logs\$date-$outputName.csv -Append -NoTypeInformation

# To see only the versions that are not matching the target version
$report | Where-Object WillBeUpgraded -eq "Yes"