What IS the right way to model dates in a pacemaker ...? I hope the answer is "just don't do it" -- but I don't know what reasons there might be for a pacemaker to need to depend on calendar dates in order to best do its job ...
Then the app pings you to remind you that your premium subscription will be expiring soon after which your heart rate will be limited to 100 bpm or less.
Also you want the pacemaker to be as air-gapped and simple as possible, because it needs 100% uptime.
(maybe I missed the implied /s)