You cannot download a new app directly on the old device if it's incompatible. However, if you "purchase" (even if it's free) the app on a newer iPhone or via a computer using an older version of iTunes (v12.6.5), it will show up in your Purchased tab on the iOS 9.3.5 device.

When downloading IPAs from the web, always be cautious. Only use reputable community sources like the community or Archive.org . Avoid sites that ask you to "install a profile" directly from Safari, as these are often ad-traps or could compromise your device's security.

The built-in Safari struggles with modern encryption. Try Puffin Browser , which processes websites on its own servers, making modern web pages load faster on old hardware.

When you click the cloud icon in the iOS 9.3.5 App Store, it will often ask: "Do you want to download a compatible version of this app?" 2. Finding Legacy IPA Files

If you’re looking to breathe life into your vintage hardware, understanding how to find and install is the key. The Challenge of iOS 9.3.5

Are you planning to use this device for a specific task, like a or a digital photo frame ?