Hey @antoine0010 , welcome to the forums! Thanks for reaching out this change in the controls.
I'm not quite sure I understand. Do you mean that, when holding shift and pressing U to upgrade multiple residents, it actually downgrades instead?
Please make sure to verify your game files, just to make sure the files are all as they should be. You'll find that step in our troubleshooting guide. Can you also double-check in the game settings that you haven't changed any of the keybinds?
It'd be great if you could clarify what is happening for me. I'll be happy to report this issue to our team to investigate further internally