Its all irrelevant when Apple (and google) provably knew its push notifications could be read by govnts but kept it secret until forced to disclose it by a legal loophole used by a right minded politician.  How much does encryption matter at all on any OS's that are required by law (in UK at least) to provide backdoors to access encrypted information which in all cases does not involve breaking encryption.  Trust in PlayStore/AppStore to install encrypted message apps is ludicrous, and any app developer that allows or encourages this cannot be trusted to secure your messages, 'unbreakable' encryption isn't the problem or solution to security on OS's run by 2-3 companies, all of them made in the US.