I'm actually impressed that their commitment to open source extends far enough to provide instructions for how to do this.

So you’d have to publish to the App Store your own patched mobile app?

You could also use testflight or distribute it internally using an MDM if you are large enough.

Wait why does selfhosting Matrix and using the Element app give me notifications for free but Zulip tells me I can pay them or recompile my app? Does that seem right to you?

It sounds like you're being subsidized by Element which may not last forever either. We're not entitled to free centralized push notifications.

That is totally wild to me. Of course we are entitled to free notifications if we run the infrastructure. Who is subsidizing my XMPP client notifications? Why has this never been a problem for any other chat client until Zulip? If literally every other chat client to a FOSS chat server can make it work without crumpling under costs, Zulip is in the wrong and should not do this.

The push notifications are a centralized service that communicates with the Apple and Google push notification service. All those Element/XMPP/Zulip/etc apps run their own infrastructure that receives the notifications from your self-hosted server and passes it along to Google/Apple.

If you run an XMPP server and an iOS client for example you'll see in your logs that your server is connecting to, e.g. push.tigase.im or whatever if you're using Siskin. Another server for Monal. Another one for ChatSecure. and so on.

And they break. Monal for example rate-limits connections which leads to no push notifications for a while.

It's not unthinkable that they will either fold and follow the current trend or stop offering the service altogether, if it really does cost.

That's just plainly wrong. A push notification will wake up the app for 30 seconds and in this timeframe enables it to receive all new messages directly from the xmpp server. When Monal receives an additional push message within these 30 seconds, the background time is increased by apple for another 30 seconds, resulting in a higher power consumption without any benefit. That's why our pushservers ratelimits (lets better call it: deduplicates) pushes to 2 per 30 seconds.

Ceasing to operate our pushservers would be the same as ceasing to develop the app itself. And that would be bad even if no pushservers were needed. So no, it is indeed unthinkable to stop offering these pushservers. If you want development and the operation of the push servers to continue, you can always donate some money. Currently our funding especially for the push servers could be better…

Are you running the infrastructure? If push notifications go from your Matrix server to some server run by Element to Apple to your phone then Element is subsidizing you.

the push notifications are a centralized service that does go through their servers, even when you self-host the chat itself.

Yeah, but everything else being equal (using Element), I have my account on their server too, and use push messages there. Or I only use their push messages and host my own server. As far as I understand both are free.

So you have nothing to worry about, then. If you were running your own Matrix server, and wanted to use their push infrastructure.. Well you're still fine for now but who knows in the future.