IBKR recommends clients change their PIN regularly to add an extra layer of security.
If you have forgotten your current PIN and you have another security device active for your username, such as a temporary code, SMS verification, a Mobile Authenticator app or a Digital Security Card+, you can uninstall the IBKR Mobile app and then reactivate it manually, using one of the procedures below (without selecting Recover Setup, otherwise you will be required to enter the current PIN):
If you have forgotten your current PIN and you do not have another security device active on your username, you would need to contact Interactive Brokers on the phone to have your PIN reset.