Gradebook calculation changes
During upgrade Moodle will identify which courses are affected by the bug fix and freeze the gradebook calculation methods to the previous version. The message will be displayed to the teacher and teacher must manually accept the potential changes in the grades.
Below is the list of all the fixes since gradebook versioning was introduced. The 8-digit version number is the date of the fix. Your Moodle release number also contains the 8-digit number that refers to the date when this version was build. Accepting the changes will progress your "gradebook code version" from the one when it was freezed to the latest available in your current version. Please note that if you are not using the latest weekly release this page may contain the fixes that are not yet available in your Moodle.
20150619 MDL-49257 Calculation of the extra credit items weights in Natural aggregation method (version 2.8 and above)
Two bugs were fixed here. First, very critical: overriding the weight of the extra credit item can lead to changes in other items' weights and pretty random final grades. Second, the automatic weight of extra credit item was dependent on the overrides of the normal item's weights (and it should not). This especially becomes noticeable for the students that have grade items excluded them from totals (for example, when they are hidden or empty). Here you can find lots of the screenshots of before/after behaviour (note that table is very wide and the horizontal scrollbar appears underneath).
Video with the demonstration of the first bug: http://youtu.be/-mQ1cWzNuxI
The simpliest example of the second bug: The category (or course) has two normal grade items and one extra credit item. If all maximum grades are the same, the weights of three items will be: 50%, 50% and 50%. However if the weights of the normal items are overridden to be 50% and 50%, the weight of the extra credit item magically became 0%. If teacher overrode weight of the first item to 80%, the second item automatically becomes 20% (correct) and the extra credit also becomes 20% (incorrect).
Correct behaviour (after the fix): If the weight of extra credit item is not overridden, it should be itemmaxgrade / totalmaxgrade , where totalmaxgrade does not include extra credit item. In the example above the weight of extra credit item should always be 50%