I have also had these emails, some current files and some old files. I suspect this isnt a security breach but something that is happening at MYOB. I am reasonably sure in the latest update, or coming very soon, when you set up your chart of accounts that you need to enter the bank details as a default so that ABA files can be generated. Perhaps supplier and payroll bank details will also become a default. This is why I think it is something going on in MYOB, perhaps they are working on these changes and this has triggered these emails. I am on hold and started with a 38 minute wait time and 40minutes later still have a 30 minute wait time. This long delay on the help line suggests this has happened to multiple people. If I get through eventually I will post the answer to this.