diff --git a/JSON-dictionary.md b/JSON-dictionary.md
index adecdc5..91cf15f 100644
--- a/JSON-dictionary.md
+++ b/JSON-dictionary.md
@@ -45,6 +45,7 @@ Certain commands are used to alter the non volatile settings stored by the contr
 | TempMode | integer | 0,1 | From ESP | | 0=degC<BR>1=degF |
 | Thermostat | int | 0,1 | To/From ESP | **YES** | |
 | ThermostatMethod | int | 0,1,2 | To/From ESP | **YES** |0: Conventional  <BR>1: User deadband<BR>2: Linear Hz   |
+| ThermostatOvertemp | int | 0 ... 10 | To/From ESP | **YES** | shutdown heater if this much over set point |
 | ThermostatWindow | float| 0.2 ... 6.3 | To/From ESP | **YES** | degC span of thermostat window |
 | Time | string | HH:mm:ss | To ESP | no | |
 | TimerConflict | integer | timer ID | To/From ESP | | TO: test nominated timer<BR>FROM: timer in conflict |