The average temperature of the water vapor that gets hot inside the boiler can be increased by making steam as steam heat very well with high temperature without adding more pressure in the boiler.
The average temperature of the steam that has been heated by the boiler can be increased by making the steam is superheated steam at very high temperatures without increasing the pressure in the boiler.
The average temperature of the steam heated inside the boiler can be increased by making the steam is a superheated steam with high temperature, more without increasing the pressure in the boiler