With Untappd update 3.4.9 we have introduced a Floating Action Button to help simplify the check-in process. However, if you don't like this button you can simply toggle it off.
You can toggle off the Floating Action Button in your advanced settings menu:
- Navigate to your Profile Page
- Tap on Settings
- Tap on General
- Tap on Advanced
- Scroll until you see "Show Floating Check-In Button"
- Toggle the "Show check-In Button" off