Yes, da Cat is running fine with Sierra. I almost made 100 days again but the battery died on remote station. I ended up rebooting before I realized I needed to replace the battery. That also allowed me to update Sierra to the latest 10.12.6. Normally, the batteries are changed in November but the the excessive cloud cover this winter was too much for the poor battery.
The Mac Mini is a dedicated system running only WC and EvoCam v 5.0.
I was sure I had switched to EvoCam v4 because of a memory leak in v5. It appears to have no problem in Sierra. Go figure......