If you are jailbroken, you can use a tweak like DisableYouTubeUpdates or manually edit the Info.plist file of the app to change the CFBundleShortVersionString to a current version (e.g., 19.x) to trick the server into thinking you are up to date.
If the App Store method fails, you can manually install an .ipa file using a computer. youtube ipa for ios 12.5.6
Even if you install the app, Google often blocks older versions with a popup. If you are jailbroken, you can use a
Downloading an IPA for a free app (YouTube) is legally gray. Modifying it to remove ads violates Google’s Terms of Service. This guide is for educational purposes regarding legacy hardware preservation. If you are jailbroken
