If there was a heinous criminal and they were using Signal, I wonder if law enforcement could get a warrant to push an update to Signal (or even OS push service

If there was a heinous criminal and they were using Signal, I wonder if law enforcement could get a warrant to push an update to Signal (or even OS push services) through the Play Store/App Store, just for that user. Wouldn't that work? It's the same legality and hoops to jump through as a wiretap, it seems to me, and it solves law enforcement's problem. The more I think about it, the more I am convinced they could do this, but they would rather not because it's much harder, since it requires a special warrant with high evidence thresholds for each user. This reinforces the claim that what they really want is an ability to get any messaging data without a warrant, but they don't want to say so.