PVS Collection vDisk Update

Problem:
In my environment I have about 300 provisioned desktops, and when I update the vDisk sometimes it can take a while (days) before all of the VMs get the latest version.  Especially, in the case of a roll back I need a good way to get all of the VMs which are on the wrong version (and are waiting for a session) to boot to the correct version.

Solution:
POWERSHELL!!
Requirements:
I think powershell version 3, but since I did it with v4 I’ll say 4+
PVS powershell module installed (learn more here)
Powershell remoting enabled on your delivery controller (also need to supply the name in the script)

What the script does:

1. Gets a list of the Collections in your PVS environment, and outputs it to out-gridview so you can select the collection you want to focus on
   1. If you hit cancel the script ends
2. After your select the collection and hit ok it will get all of the devices in that collection which are powered on, and cannot access a maintenance/private disk image
3. For each of the devices in that list it checks to see if they have the latest vDisk version, or if they have the correct OverRide version.
   1. If they do then it tells you the device is on the correct version, and moves on to the next device
   2. If they do not then it will pass the device name to the check function, and after moves on to the next device
      1. invokes powershell on the delivery controller to see if the VM is in use (powershell remoting required)
         1. If it is, it tells you it is in use and does nothing
         2. If it is not it will reboot the vm, and tell you

Here is the script!  Remember to test it before using it in a production environment.