The mini version doesn't need hosting, it doesn't have a proxy middle man. A 16yo kid reverse engineered the protocol and then got contracted by beeper to implement it as beeper mini. It's a client directly connecting to apple like imessage native.

Will it break? I'd argue if the cost of breaking it in engineer time is worth doing to Apple, yes. All they'd have to do is roll their own crypto and reverse engineering that might be impossible. Probably easier ways to break it but then maybe it turns into a cat and mouse game.

Legally it's hard to say if it's OK too, the end user is likely fine, but the developer especially being contacted may not be since to reverse engineer it could be breaking terms of service or licensing clauses though I'm not really sure what kind of damages could be claimed. To reverse engineer they had to use the original on jailbroken iphones to go through the engineering discovery.

Anyway the point is, it's not going through beeper or anywhere other than Apple. So there's no component to host. It's different to beeper.