Just installed ATM10 version 2.23 and found the shaderpacks folder empty. I didn't see anything in the hotfix text that said shaders were being removed, so I assume this was an oversight. Just an fyi.

To fix for now, I just copied the shaders from my previous 2.22 installation and it works fine.

EDIT (in case this is helpful): To be clear, I do not use the Curse launcher. I use the ATLauncher, and I never "upgrade" a pack. Instead, I install a fresh copy of the updated modpack in a new folder, copy the necessary sub folders and files from the old version to the new version (i.e., journeymap, local, saves, etc.), and play from the new instance. But I never copy the old shaderpacks folder because I want to rely on the new version of the modpack to install the shaders in case they have been updated.