Do you have installed a program which is advised to run in an older version of Window than what you have in your system? If yes then don’t worry you can still make a program compatible to run in different version of windows.
Right click on the program which you want to run in an older version of windows.
From the menu select and click on “properties”
Now click on “compatibility” tab.
Now select the older version of windows for which you want to run the program.
Then click on “Apply” and “OK“.
In this way you can make a program compatible to run in older version of windows.