Shorts was heavily optimized for newer versions of Android. On 5.1.1, the Shorts shelf may load, but scrolling through Shorts will be choppy. Use the normal video shelf instead.

Let me know and I'll give a more precise answer!

Yes. Google deprecates older app versions by updating their API backend. Typically, a YouTube version remains functional for 18-24 months after its release. Expect 17.09.38 to fully work until mid-2024. After that, you may see "Update required" messages. At that point, downgrade to 16.29.36 or switch to a web-based alternative like YouTube Lite (via Firefox for Android).

YouTube v12.19.56 or v16.x (Lollipop Compatible).

“Which YouTube version worked best on your Android 5.1.1? Comment below to help others!”

: Open your browser (like Chrome or Opera Mini) and navigate to m.youtube.com.