Metamer version 1.1 is the first release as a Universal App, superceding version 1.0. This should run natively on both Intel and Apple Silicon Macs, on all versions of macOS from El Capitan to Big Sur beta 4.
It’s now available from here: metamer11
from Downloads above, from its Product Page, and via its auto-update mechanism.
If you’re running an Intel Mac and have any problems, please let me know. I’ll leave the original Intel-only release available on its Product Page in case you’d prefer to revert to that.