Q: I am checking the Integration Services version of my Windows Server 2012 guest virtual machines (VMs), and they have an older version than the one available on my Hyper-V server, why?
A: An update was made to the Hyper-V Integration Services for Windows Server 2012 and Windows 8, related to backup operations, which incremented the Integration Services from 6.2.9200.16384 (the RTM) to 6.2.9200.16433. This was part of update rollup KB2770917. When the Hyper-V host reboots, it updates its VMguest.iso file with the latest integration services.
This means unless you updated the integration services on your Windows 2012 or Windows 8 VMs (and Windows Server 2008 R2), they will be running an older version of the Integration Services. You can confirm this by looking at the VM's registry at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Virtual Machine\Auto\IntegrationServicesVersion for the IC version, or from the host by using this command:
Get-VM | ft Name, IntegrationServicesVersion
To update the easiest way, extract the content from C:\Windows\System32\vmguest.iso from the Hyper-V host to a folder, then launch the setup.exe from the relevant support\<architecture> folder on each VM. For example:
\\savdalhv01\software\Tools\Hyper-VISLatest\support\amd64\setup.exe /quiet /norestart
Note that this will require a reboot of the VM at some point, but the /norestart suppresses.