It is easy to forget, but during the era of version 5.9, Google+ integration was still a priority. Comments and sharing were heavily tied into the now-defunct social network. Opening the share menu in this version would prominently feature Google+ circles.
On the old Galaxy Tab S2, modern YouTube is essentially unusable (stutters, overheats, crashes). Version 5.9.0.13 runs like greased lightning—fluid 60fps playback on 720p. youtube version 5.9.0.13
Or something else?
Optimized video playback meant less lag and smoother streaming, even on slower internet connections of the mid-2010s. It is easy to forget, but during the era of version 5