Important: For security reasons, you can only change your linked bank account once every 3 months.
Update the app to the last version, then go to Settings > My Profile, unlink your IBAN, then make a deposit from the new bank account which will be linked automatically.
Be aware: If you have an automated Investment Plan using direct debit (SDD), changing the linked bank account in your BUX account will switch your Investment Plan deposit option from automated to manual.
If you’d like to continue funding your Investment Plan automatically, you’ll need to authorize your new bank account in your existing Investment Plan after linking it.