I haven't seen any hint that the Critical Alerts entitlement would use any special infra compared to regular push notifications. It's just metadata in the noti

I haven't seen any hint that the Critical Alerts entitlement would use any special infra compared to regular push notifications. It's just metadata in the notification body indicating to the device to ignore silent mode etc. It's e.g used by Pagerduty [0]. It's just a way to override notification settings. The software for the systems you mention have this entitlement (or some equivalent), but are otherwise completely unrelated to this. [0]: https://support.pagerduty.com/main/docs/mobile-app-settings#configure-ios-devices https://support.pagerduty.com/main/docs/mobile-app-settings#...