If you need to update your business logo, you will need to visit the Location Details area of your Untappd for Business account. You will find this under Settings at the bottom of the left-hand toolbar.
Upload your logo at the top of the page with a .png or .jpg file. The image dimensions need to be at least 200 x 200 px and the overall file size must be under 2MB.
Once you've done this, your logo will display on Untappd and on your menus!