This morning Olympus Japan issued the following note:
Currently, we are using our software OM Workspace to update the firmware of our digital cameras, but due to security enhancements associated with macOS updates, there is a possibility that camera firmware updates may no longer be possible.
Therefore, if you have cameras or lenses that have not yet had their firmware updated, we ask that you update them as soon as possible.
Please note that Windows update services will continue to be available.
We hope that you will continue to use our products.