What does it mean to be notified of the change of minimum living allowance by SMS?

It means that you may not be a low-income household.

The change of subsistence allowance means that the family economy has improved and got rid of poverty. It is also possible that the family population has changed, such as giving birth to a child, or the old man died, and then the child got a wife and the daughter got married. Consult the community or social security center specifically.