Is it possible to change the calendar from Gregorian to something else?

The calendars of many people in different parts of the world are local and specific to that place. Is it possible to personalize the calendar (for courses) and change it to Chinese/Hijri(My case)/etc?

Hi @perpi! I have absolutely no idea. Calendars are used in many different places in Open edX, and I guess there will be different solutions depending on where you will change to change the calendar.
If you do find a solution, please post it here!

Isn’t open edX using MomentJs? If yes, I think locals are suported somehow.

on where

Everywhere! Wherever the user encounters the calendar! For a functional localization, it is necessary to convert all dates to the local/national calendar used by the user.