Thanks for the tip, for some reason, I didn’t use the retain flag.
Do you have any idea why the “free memory” jump ?
BTW, my other nodemcu board dies and would’t restart sometimes(in this case, if I pushed the RST button on the board, the Serial would print “{null} {null}”. After several times pushing, the board will restart successfully), is there some solution to make sure it will restart（like I did with the ESP32 by connecting the EN to the VCC)?