Looks like it's planned.

https://github.com/orgs/chattocorp/projects/1?pane=issue&ite...

Note that to send notifications to an iOS app, the app publisher has to send them. This means that they need to run an event forwarding proxy service (this is how Mattermost and Element/Matrix and presumably some/all of the ActivityPub clients do it), or selfhosting your server means you must also selfpublish your client app via the App Store and Apple’s developer program tax.