The compatibility Check popup is opened by pressing the 
button. Then a popup like below is shown:
In this popup the device type, the firmware version and the so-called PM Compatibility version are given for each of the devices in the plant.
The Power Management (PM) compatibility version is a number that can be used to check whether devices in the plant are compatible in terms of power management. In order to investigate the differences between the different PM compatibility version numbers, the button View PM change log can be pressed. When the user does that, a PDF document that lists the details between the different versions is shown.
On top of that we have made an overview over what software version's can run together here:
https://deifsupport.freshdesk.com/a/solutions/articles/80001085022