A new plugin released this week in the Moodle Plugins database is Grade Distribution report plugin which allows for viewing the distribution of student grades for a course regarding the current grade letter boundaries as well as changing these to shift the distribution.
Usually the grades needs to be informed to students at the beginning of the term however there may be some cases when you need to update the letter grades. The grade distribution visualizes the grades of students. Changes to letter grades (i.e. the boundary of a grade) can be analysed visually, saved and therefore overwritten if necessary.
Complete details about the plugin can be found on the documentation page here. You can download the latest version of the plugin from this link.
Have you ever changed the grade boundaries in between your course? How you have informed them to all your students? Do let us know in the comments below.