On Google Maps for iOS (version 18.104.22.168671 as of the time of writing), I can save offline maps using the hidden trick described here. This works fine. However, Google Maps also wants to update offline maps periodically (every 30 days, I think). It has an irritating habit of popping up a dialog asking for this when I'm not on WiFi (when I don't want to update, because 3G is slow and expensive). I normally cancel the dialog (I'm in the middle of doing something), but I can't find a way to force the update when I'm back on WiFi later in the day. This means I get the same irritating pop-up the next day.
Is there a way to force or manually trigger the updates to the offline maps?
(this is on an iPhone 5s, if it matters).