you can not update the Android version on the T6, no
You can play with .apk file installs. Do that thru Kodi > Programs and the there are a few ways to do it.
Use the AppInstaller or File browser or ES File Browser
You would take an .apk file like progtv
Code:
https://apkpure.com/progtv-android/com.progdvb.progtva
Put that apk onto a USB drive and insert into T6
Open AppInstaller and find the USB and open that. You should see the content of USB now. Find your apk there and click on it to install.
That app can be used with m3u Playlists.
File browser or ES File Browser will install the apk in similar fashion.
Then find the Player in the Programs (on the Kodi bar) and in Android Apps
With some of these Players, they work okay on the older Android OS
Players I have installed and used on the T6 include...
ProgTV - this is a long time supported app and has many functions, and not just a m3u Player.
PlayList Loader - m3u Player
Simple IPTV with mxPlayer -m3u Player
VLC Media Player - not much success seen with this.
I been looking for an app called WEB (TVonWEB Emulator) ... it is a Stalker emulator and I wanted to try it on the T6
That app comes included in the Avov's Market and I have used it on that box, but yet to find it in apk version to try on this T6
There are endless possibilities with these apk installs.