[gruez]

>it's even worse than that. What's additionally happening is they're still 'syncing' back to Apple servers via APNS (and to Alphabet servers via Firebase on Android)—even with notifications completely disabled, that's correct.

Source? I don't think either OS implements notification syncing between devices, it's only one way, and as others have mentioned, the actually push notification doesn't contain any message content, only an instruction for signal to fetch and decrypt the message.

[dataflow]

> I don't think either OS implements notification syncing between devices

Can't speak for iOS and no idea if this relates to the above functionality, but Pixel lets you deduplicate notifications across Pixel devices.

[pxeboot]

> I don't think either OS implements notification syncing between devices

iOS does. This is how you can receive Signal notifications on your Apple Watch and other Apple devices that don’t have the app installed.

[schrodinger]

This sounds correct. When I implemented push notifications for an iPhone application, I remainder needing to obtain a store a separate token for each device a user has, and subscribing to a feed of revoked delivery tokens. Seemed like an interesting design intended to facilitate E2E encryption for push notifications.

[jerlam]

I do wonder how notifications that are synced/mirrored to the Apple Watch and newer versions of Mac are handled.