Update and solution I was so close... the only thing which was needed was to run the older update utility with the "/f" parameter. After that firmware has been downgraded and I can run 4k[NAME] again. Thanks for nothing! 
Hello! This is my very first post here, so please let me know if this is the correct category... I have a Dell WD19TB docking station. Till today everything was fine. After running DellDockFirmwarePackage_WD19_WD22_HD22_Series_01.00.09.exe the station has been upgraded. But after that I cannot run 4k with 60Hz. Max is 30Hz (I have also option 50Hz, but after picking that, monitor goes black with information "no DP signal"). I have contacted Dell support, they told me that this is a known issue, but to create a ticket they want me to provide Dell order number, which I don't have, as I have bought a used docking station. Is there any chance to perform a firmware downgrade, or do we know when this issue will be fixed?  Thank you in advance,Przemek
WD19TB after firmware upgrade not able to run 4k with 60Hz