On Android, it’s easy to install older versions of apps on your device through sideloading. However, iOS tends to lock things to the App Store, in the name of user safety (and, of course, money). If an app no longer supports your device, you’ll likely see yourself blocked from downloading it. But as it happens, iOS has a built-in solution for this issue—one it doesn’t advertise.
To download old versions of apps that will run on your unsupported device, open the App Store, then tap your profile icon in the top right, and go to Purchases. Here, you’ll see a chronological listing of every app you’ve ever downloaded from this Apple ID (which you can use to figure out the first app you ever downloaded, if you’re curious). Scroll back until you find an app you’d like to have on your device, but is technically not supported, then tap the adjacent iCloud download symbol.
After you wait for the system to load, you’ll see an alert telling you the current app is not supported on your device, but an older version is. From here, tap “Download,” and an older, supported version will install on your iPhone or iPad. After that, you’re in.
More info about what to do if you never bought the app in the past at the link below.
See How to Install Unsupported Apps on Older iPhones
You can download old versions of apps that will still run on your unsupported device.