What are the levels of severity of errors in software?

There are various approaches to classifying the severity of bugs, but the most common levels are:

• Blocker: A bug that completely blocks the operation of a critical function or the entire application. It prevents further testing. Requires immediate fixing.

• Critical: A bug that causes the complete non-functionality of a significant part of the functionality, data loss, or application crash. Work is possible but with serious limitations. Requires urgent fixing.

• Major: A bug that disrupts the operation of a significant part of the functionality or causes incorrect data display but does not lead to complete non-functionality. Workarounds are available. Needs fixing before release.

• Minor: A bug affecting secondary functionality, usability, or appearance but not blocking work. Not critical for release but desirable to fix.

• Trivial: Cosmetic bug or typo that does not affect functionality. Does not require urgent fixing and can be fixed at the next opportunity.