This is put in logs: [main/WARN]: WARNING! Mod screenshotclipboard is only using deprecated 'modmenu:clientsideOnly' custom value! This is no longer needed and will be removed in 1.18 snapshots.

In the latest modmenu release for the 1.18 snapshots (21w38a is latest currently) of minecraft, the deprecated api has been removed. This is now more important to remain 1.18 compatible.

I already made this change in 2b97c5e, but for some reason didn't push it!