If you have downloaded YouTube in the past using your current Apple ID, Apple allows you to download the last compatible version designed for iOS 12. Step-by-Step Instructions: Open the on your iPhone or iPad.
Some third-party tools require your Apple ID credentials to sign apps. It is highly recommended to use a secondary, throwaway Apple ID for this process rather than your primary personal account. install youtube ios 1257
If you successfully installed the older app version but get this error message, it means Google has deprecated the API version your app uses. If you have downloaded YouTube in the past