This site I updated was on 1.8.2 before. I updated to 1.9.2. I replaced the app and admin folders, as well as the index.php and admin.php files in the root directory. I also deleted everything in the cache folder. To be clear, all fields were working properly before I updated.
After I did that, creating a new post looked like the attached screenshot. I know it's probably me – I probably did something wrong when I updated. But I have no idea what that was! Help?