in the top right corner on the budget screen, the subscriber/budget owner field has been replaced by two options where you can:
Watch or unwatch a budget
Set sharing permissions
Watch a budget
If you "subscribe" to a budget, or, using a new terminology, watch a budget, you will receive all notifications for that budget.
To unwatch a budget, simply click on the eye icon again, and it will be crossed out.
In the sharing options, you can select specific members of your team, or add teams that you want to share this budget with:
When added to the list, those teammates and/or teams will be able to track time and expenses against services added to that budget: