I recommend not installing anti theft if you plan to change sim

the correct and easy way to change the SIM with Anti-Theft installed is:

  • open Anti-Theft and deactivate it
  • change sim
  • open Anti-Theft and activate it

when you open Anti-Theft after the SIM change the new SIM gets added to the list of trusted SIM cards.
by deactivating it before the change, you make sure that no SMS is beeing sent at all.