Likely near the end of this year (October?), Microsoft will make the new Unified Interface mandatory on all Dynamics 365 Online instances. Until then, we can choose between this new UI and the Classic Web Interface. Here are the steps to do that:
Now if you go back into the D365 instance, it should display the Classic Web Interface or the new Unified Interface depending on how you set it up.
My name is Rick Towns and I am an amateur astronomer and computer programmer from Canada. This is a collection of interesting posts I've gathered over the years.