Is there is any possibilities to downgrade from 3.1 to 2.8 moodle.If yes, then how to downgrade
I am afraid this is not possible, only thing you can do is, start fresh from 2.8 and import courses.
btw, what's the reason of you thinking of downgrade?
@Usman , thought of working in 2.8 instead of 3.1 and i thought it will be complicated to install and work with both 2.8 and 3.1 in same system
Pretty sure that you cannot restore courses from a newer version of moodle...
It's not *supported*. It's worth a try if you are desperate.