If you choose not to jailbreak, here's how to install a modified YouTube app using a computer tool:
The official YouTube app in the App Store requires a much newer version of iOS. When you try to download it, Apple tries to give you the "latest compatible version." However, for many users on iOS 9, this handshake fails, resulting in a or "Unable to Purchase."
However, I can offer a short informational essay on the topic: download youtube ipa file for ios 935 fix
In the YouTube app, go to Settings → General → Enable "Use HTTP instead of HTTPS" (older versions have this). Fix 2: Install TubeFixer (a tweak from Cydia repo https://cydia.ichitaso.com ) to restore API compatibility.
Even after installing an older version of YouTube, you may encounter "Connection Error" or "Content Unavailable" messages. This is because the app's internal protocols become outdated. A jailbreak allows you to install community-made fixes, such as: If you choose not to jailbreak, here's how
Connect your iOS 9.3.5 device to the computer via a USB cable.
Cydia Impactor is a popular tool for installing IPA files on iOS devices. Here's how to use it: Even after installing an older version of YouTube,
: If you haven't "purchased" it before, download it first on a newer iPhone/iPad using the same Apple ID to make it appear in your older device's "Purchased" list.
You must have Cydia installed. For iOS 9.3.5, use Phoenix jailbreak.
If you do not wish to jailbreak, accept that the sideloaded IPA will require weekly re-signing — use (legacy version) for semi-automation.
If you simply need "YouTube in the background" or "No ads," you are out of luck on stock iOS 9.3.5. The CPU cannot handle modern decryption.