🔧 Configuration:

•	apcupsd is installed and running ✅
•	UPS (Smart-UPS 1500) detected and reporting via USB ✅
•	/etc/apcupsd/apcupsd.conf includes:
•	ONBATTERYDELAY 6
•	TIMEOUT 600 (shutdown after 10 min on battery)
•	BATTERYLEVEL, MINUTES also correctly defined ✅

⚡ Simulated Tests:

•	Manual onbattery trigger tested ✅
•	wall terminal alerts confirmed working ✅
•	msmtp email integration now fixed (no -s error) ✅

🧪 Shutdown flow:

•	apccontrol runs doshutdown, which calls:

/sbin/shutdown -h now “apcupsd UPS forced shutdown”

✅ The correct command for Proxmox to shut down cleanly.

✅ Final Summary: Yes, Proxmox Will Shut Down Automatically

If the UPS:

•	loses mains power and
•	stays on battery for >10 minutes (or any other threshold we set)

→ Proxmox will shut itself down safely, thanks to apcupsd.