For users still operating on iOS 10.3.4 (typically on an iPhone 5 or iPad 4), the official YouTube app from the App Store has long since dropped support. To get the app working today, you generally need to sideload a legacy IPA and apply a version "spoofing" tweak. Download Link & IPA Sources Internet Archive (Official IPA Repository): You can find a comprehensive collection of YouTube IPA versions that were once compatible with 32-bit devices. Pre-Modified IPAs: Some community-sourced Google Drive links like this iOS 10.3.4 YouTube IPA provide versions specifically intended for legacy use. How to Fix the "Update Required" Error
YouTube IPA for iOS 10.3.4: Download Links and Installation Guide youtube ipa for ios 1034 link
Since older tools like Cydia Impactor are largely deprecated, is currently the best free tool for installing IPAs from a Windows or Mac computer. For users still operating on iOS 10