Excel 2013
To get KODIAK Excel Functions to work with Excel 2013 the GeniusFunctions.xll addin file needs to be added again.
Choose File -> Options -> Addins
On the bottom of that dialog there is a "Go..." button. Make sure that "Excel Add-ins" is selected and press that button.
A window with selected addins appears. Choose "Browse..." and go to C:\\Users\USERNAME\AppData\Roaming\Kodi\KodiakExcel and choose the GeniusFunctions.xll file.
After selecting this file Kodiak Functions should work.