@Abhishek_TV @HSR... I updated to Oreo. Feedback as follows:
1. Update process: smooth. ~15 min + ~10 min post log in.
2. UI: looks good, but nothing like the fluid nature of 7.1.2. System menus lag and the scrolling is jagged. It's improved a bit after several scrolls, but still below the 7.1.2 level.
3. Touch: seems somewhat dull compared to the very sensitive touch of the Nougat srt. Frequently you can see the touch registered on screen, but no response. One needs to very consciously touch the screen.
4. Battery: seems around the same as Nougat srt.
5. Signal and sound: Jio signal is now indicated as weaker in the network indicator, but no adverse effect on sound quality. Mic and speaker are clear.
6. Fingerprint scanner gestures: Registered prints without issue. Locks well. But unlocking seems numb compared to the Nougat srt. Double tap to lock seems to work only when gently tapped with the flat part of the finger used. Fingertip tapping does not work.
7. Improved: oddball call termination beep (which was annoyingly loud in Nougat srt) seems well behaved and quiet now.
Have not done a factory reset yet, as I'm actively using the phone and cannot afford the long drawn app reinstallation processes.
Rating: 7/10, purely because of the superlative experience of the Nougat srt, which is a hard act to follow.
To improve: UI scroll, touch sensitivity and fingerprint sensitivity.
Phone still rocks.