One of the accessibility issues I see more often in iOS apps, believe it or not, is unlabelled elements. This happens especially for buttons with an icon but no title. In those cases, you need to configure an accessibility label manually.

Calendar of the Advent of iOS Accessibility. Day 1. Buttons with no labels (especially buttons with an icon, but no title). Button with a bell, that intends to let the user see the notifications. If the button has no accessibility label, VoiceOver could say things like: button, bellIcon, possibly notification... far from ideal! A good accessibility label would be