Will Apple allow replacing a free app with a subscription app?

Question

iOS

Hello!
There was a following question: I want to write application.
Test and expand its functionality and not take money for it.
But, when I reach a certain stage, add subscriptions to the application.
Is it possible?
Will Apple allow replacing a free app with a subscription app?
Perhaps I will have to make a separate paid version?

Answer 1

Add a purchase/subscription in an app update . Paid application can be made without updating.

Answer 2

So make it paid or add a subscription? These are two different things.
You can add a subscription at any time.