In the field of software development, the version number is usually named in the format of "major version number. minor version number. revision number", also known as "XYZ" format, where:
- Major version number: when you make an incompatible API modification;
- Minor version number: when you make a backward compatible functional addition;
- Revision number: when you made a backward compatible bugfix;
For example, if the current version number is 1.2.3, then:
1 is the major version number, indicating that this version has an incompatible API modification;
2 is the minor version number, indicating that this version has new functions that are backward compatible;
3 is the revision number, indicating that this version has a backward compatibility bugfix.
When development cycles are longer or releases are more frequent, multiple revision numbers may be required, such as 1.2.3.1, 1.2.3.2, etc. Also, some developers use dates or other similar identifiers instead of version numbers.