Developers who opt for tier one will get access to a limited set of mandatory App Store services, including:
* App distribution and delivery
* Trust and safety features
* App management
[...]
Developers who opt for tier two will get access to all services provided by the App Store today.
The document says manual updates are included but not automatic updates (which is just a setting in the App Store that I personally disable).
Whether there will be update notifications is unclear. Is that what you meant by "app notification delivery", or something else?
As an App Store developer myself, I would love to have Tier 1 in the United States, mainly due to no user ratings and reviews. I hate them, and I hate trying to solicit them. As far as I'm concerned, ditching ratings & reviews would be a bonus!
Apple will do whatever they can to ensure that developers that don't pay will suffer the costs.
That's fine with me. All of my empirical evidence over the years suggests that my customers are coming mostly from the outside, and Apple is not bringing me many customers from inside the App Store.