Why have booking IDs changed overnight

Why have booking IDs changed overnight

Hi there - up until yesterday, I was able to specify the format of my Booking IDs - and I had them organised, with follow-on actions in CRM based on the ID. eg: 


But from today - this option seems to have disappeared, and all my booking IDs are now looking like this: 


Why has this change been made, and why has nothing been announced about it? We have workflows that are based on a stable system - we can plan for changes but only if you tell us about them ...