If your digital menus app has been shutting down or you're unable to find the digital menus app on your Fire TV stick, you'll want to make sure you're using the latest version of the app.
You'll also need to make sure your version of the Fire TV stick is compatible with the app. To check your Fire Stick compatibility, you'll need to go to the Amazon account that the stick is attached to (most likely the account used to purchase the stick) on a laptop or desktop. From there, either search for the Digital Menus by Untappd App, or, follow this link: https://www.amazon.com/Untappd-Digital-Menus-by/dp/B08PJP5R3S
On the right, click the link in blue to view your compatible devices.
You'll see either a green checkmark indicating your device is compatible or a red X showing that it's not:
To update the app, select your device from the Deliver To dropdown and click the Deliver button:
OR go back and choose "Cloud Only" to make it available to all compatible devices.
You can also open the "Digital Menus by Untappd" app directly on your Fire stick using the Find feature on your Fire TV homepage. Search either "Untappd" or "Digital Menus by Untappd" to bring it up:
When you open the app, if you see the image below on your screen, you'll know there's a newer version of the app available for you to install:
With your remote, select Update. You will be redirected to a page where you can download the new version of the app.