UNO WiFi Rev 2

when i upload a Sketch to an UNO WiFi Rev 2, i get the following error:

"avrdude:WARNIG:invalid value for unused bits in fuse "Fuse5", should be set to 1 according to datasheet. This behaviour is deprecated and will result in en erros in future Version. You probably want to use Oxcd instead of Oxc9(double check with your database first."

i have no idea what it mean.

You can safely ignore this warning. If the time ever comes that Arduino updates to a new version of avrdude that doesn't support the old style handling of unused fuse bits, they will update the fuse values at that time. For the foreseeable future, either fuse value Oxcd or Oxc9 will work just as well.