something has changed in display for Yahoo Mail and Google messages. The fonts are very large and spacing is large. The web pages still normal so it doesn't help trying to change font size.
Is it just the fonts inside your messages when you click on a conversation is that the text that's bigger or everything in the whole app. If you open Google messages and the conversations have large text then you may have accidentally open the pinch and expanded the screen just pinch it closed and you'll get normal size fonts I assume the same might be true of Yahoo mail
