Severity (S) is the indication of bug’s effect and impact on the customers. For any new bug, this is the first thing to be determined while filing the bug.
Typically, severity is divided into five levels and are: S1 (Highest), S2, S3, S4, S5 (Lowest)
- S1: means that the feature can’t be tested or blocking further testing
- S2: majority features are not working, and many tests are failing
- S3: some cases are not working
- S4, S5: very corner cases and not impacting the major functionality
The bug filer would determine the severity and set while filing the bug.
No. Typically, once set the severity in the bug, then no changes can be done. Typically, bug tools will not allow changing the severity.