Can someone tell me what the "rules" are regard app content updates? In other words, does an app only check for new or revised content when it is first launched? Or is it continuously pinging for new content? Or, is there a way to tell the app to refresh and look for new content. And by content, I mean articles, layouts, and cards.
Your summary is pretty much right. We'll check for updates whenever you go into a collection and whenever a browse page is shown. That refresh happens in the background though, so we don't interrupt the flow of the reader through the app. Once we know about the update we'll show the update pill (if the reader is on the browse page) or just auto-apply the update when they enter into the collection again.
Cards and layouts update came in recently, and I'm not sure that's been deployed to beta yet.
In my observation, it checks for new content each time the screen is refreshed. So, If I'm in an article, and I nav back out to the collection level, I'll be alerted of an update, If I go from one collection to another, I'll be alerted of an update, or If I quit and relaunch (like you're sugguesting), I'll be alerted of an update - if one is available.
I've noticed, it's also dependent on your internet speed - sometimes the updates come through almost instantaneously, sometimes it may take a few minutes.