I only speak from what I have read on the forum while worrying about the high cost of changing the thermostat on my 2012 XC70 which I would do routinely if it wasn't for the expense and great difficulty in doing myself. I don't know exactly when the change in design happened but it seems to go back as far as 2009. See this for information:
https://www.volvoforums.org.uk/showthread.php?t=197671