Modern YouTube uses AV1 or VP9 codecs, which your iPhone 4S processor cannot decode.
Many "YouTube to MP4" websites are now serving malware tailored for older OS vulnerabilities. iOS 9.3.5 is vulnerable to the "Trident" exploit (used by Pegasus spyware). Do not install random configuration profiles or third-party app stores (like TutuApp or AppValley) from Safari on this OS. You risk bricking your device or leaking your Apple ID.
If you never downloaded these apps on a newer phone using the same Apple ID, they will not appear in your purchased history, and you cannot use this trick. Youtube Download Ios 9.3.5
For users who did not hoard
Keep that iPhone 4S alive, but understand that YouTube is slowly shutting the door on legacy operating systems every single week. What works today (May 2026) might break tomorrow. Modern YouTube uses AV1 or VP9 codecs, which
Open VLC on your iOS 9 device. The video will be there. This is 100% reliable.
However, if you love vintage tech:
If you are desperate and willing to risk security, jailbreaking iOS 9.3.5 is trivially easy (using or Home Depot ). Once jailbroken, you can install Cercube for YouTube (Legacy version) or YouTube++ .
This article explores how to download YouTube videos on iOS 9.3.5, covering workarounds, legacy apps, and the "grey market" of third-party tools. Do not install random configuration profiles or third-party