Sometimes there’s a short delay between the release of a game update and its appearance in the app store. This is a normal occurrence and usually resolves quickly.
If you're not seeing the update:
Search for the game manually in the app store, rather than tapping the in-game update pop-up.
Try using your app store’s “Update All” feature this can often trigger the update to appear.
Once the update shows up, simply tap “Update” to install it and get back to playing!
If the issue persists after trying these steps, waiting a little while and checking again usually solves it.