Hi FA_CM , it's not strictly an error at MYOB's end, but it is a deliberate change to previous API behaviour, which has caused several add-on programs to throw errors instead of just working. This change was announced some time (maybe a month or two?) before it was implemented, but the implications may have been missed.
Besides, it's hard to test against a change which has not been made. MYOB bear some responsibility; maybe a new version of the API should have been made available (separate version number, heavily publicised) before sunsetting the current version. That would have given all developers time to make their changes.