Some of the devices have limits to their iOS versions so they can run and not cause issues.
Try this:
If there is a profile icon on the top right:
- Install the app on your computer if it is not on your iCloud account.
- Click the profile icon on the top right.
- Go to purchases.
- Scroll until you find the app, and without opening the page for the app, click the blue cloud.
If there isn't:
- Install the app on your computer if it is not on your iCloud account.
- Click purchases in the bottom tab.
- Scroll until you find the app, and without opening the page for the app, click the blue cloud.