I am also interested in using the zone triggers from Home Assistant https://www.home-assistant.io/integrations/elkm1/ Uses the function SERVICE ELKM1.SENSOR_ZONE_TRIGGER
Cause a zone on the panel to trigger. This command creates a virtual momentary open condition on the zone as if the EOL hardwired loop had been physically opened.
I didn’t have it working, but if I understand from your testing above, the Input must have a physical jumper, so additional MXIN cards would be needed for jumpered inputs rather than a virtual input.
Does the input jumper require a terminating resistor? And needs as the normally closed wiring examples?
Any indication if a firmware roll-back is required for 5.3.18?