The workaround involves setting up a Text Replacement for the letter "i". To do this, go to Settings -> General -> Keyboard -> Text Replacement, and tap the plus (+) button. In the Phrase field, type an uppercase "I", and in the Shortcut field, type a lowercase "i". This should fix the problem until Apple addresses it properly in the next iOS update, which shouldn't be far off.
Apple is separating the new smartphones into its usual low-cost versus high-cost categories, with big differences between the two models coming down to the camera, display, and battery life.