You will need to change your mobile number within Online Banking if app alerts are going to an old phone number.
Log into Online Banking and update your number using a card reader.
Please note, once you have changed your mobile number and you register for mobile banking app. As a security measure you will have to wait 3 full calendar days (starting from the next day) before you can request your mobile banking activation code. During this time, you will not be able to access the mobile banking app, however you are still able to use Online Banking.