I checked this on my Moodle website, but minimum grade can not be edited.
I also checked it on the Moodle sandbox.
Please follow these steps:
- Add an assignment
- Go to gradebook setup
- Go to edit grade item of the assignment you just made
- Try to edit maximum and minimum grades, it is impossible (grayed out)
The maximum grade can be set under the assignment settings, topic 'Grade'. But the minimum grade can not be set anywhere.
Can someone please confirm this?