In 2011 I bought the Navigon GPS navigation app for iPhone/iPad on a ½ price sale, mostly using it with an iPhone 3GS. When the iPhone 4S was released the following year, I ordered one asap. It duly arrived & I set it up by restoring from an iTunes backup of the 3GS. Everything worked well except for Navigon. It just didn’t look right. After a week I took it to an Apple Store to get it checked out.
It passed all tests with flying colours, so it should, it was new! Except for this bloody navigation app. In desperation the expert swapped the phone over for an identical one, I had my laptop along & restored the first 4S’s backup to the new one. But nothing changed, it wasn’t a hardware issue, we assumed. I went my merry, if somewhat confused way without a resolution to the problem.
It turned out that the problem was resolution. The 4S had a Retina screen, but not so the 3GS. About 6 days afterwards, an update to Navigon arrived, CALIBRATED to suit the higher resolution screen of the 4S. Ultimately, the resolution of my issue was greater resolution.