One thing missing

This is a great app, I bought both of this developers apps. The one thing that is missing, that I find absolutely necessary to update, and have told the developer many times about, is the fact that you can only start the week on Sunday. As you know half of the planet starts their week on Monday. So I really dont understand why this cannot be given as an option.
The developer has not yet updated this crucial feature.

oikset about Productive - Habit Tracker, v1.3.4