Here are my 2 cents:
1. If you have CUSTOM firmware (1.08 or earlier) installed you should FIRST go backup to official Firmware of the same level before upgrading to android 7 Firmware 2.0, it is based on my own experience, I could not upgrade until I went back to the official one.
2. Clock does not show the correct hour even after correcting your time zone, you have to reboot to fix this.
3. Switching back to HDR AUTO from SDR results in blank screen, I had to reboot and apply the change again, (I had to to choose SDR to be able to switch off imprex engine and all it's settings and correct my contrast-brightness etc options.
4. Sound seems to be working well, I tried different files and 7.1 DOLBY ATMOS and DTS:X are working fine, in fact, I think it is richer somehow
5. Picture quality seems more or less the same, but more sensitive to brightness and contrast: Before upgrading I had 51 in brightness and 54 in contrast and they seem to bright now with a bit washed away background.
I still have to try KODI. I haven't had time yet but will post my experience later.