It's always annoying to have something that was free taken away from you, but this seems pretty fair. There's no way to handle push notifications without a centralized server.
You can complain that $8/user/month is too expensive for hosting a service that probably does not require much in the way of infrastructure. Well, you can host your own, it's just a pain. And all of the code is open source, so if someone else thinks they can offer Zulip hosting for cheaper, they are free to do so.
You can complain that $8/user/month is too expensive for hosting a service that probably does not require much in the way of infrastructure. Well, you can host your own, it's just a pain. And all of the code is open source, so if someone else thinks they can offer Zulip hosting for cheaper, they are free to do so.