"Version 1257 isn’t a secret key — it’s a red flag. Download safely: use Premium or build a trusted Shortcut yourself."
Sometimes, even the "last compatible version" of the YouTube app can be buggy or slow on older hardware. Many users on iOS 12.5.7 find that the mobile website actually performs better. You can turn the website into a "pseudo-app" on your home screen: Open and go to ://youtube.com . download youtube ios 1257 link