SemVer defines a de-facto standard for managing multipart doted version numbers in the form:

{major-version}.{minor-version}.{patch-level} 

The version number can be followed by a pre-release label.

Examples:      0.3.0      development version before any initial release
               1.0.0      first public release
               2.1.155    release with a patch level 
               3.0.0-rc1  pre-relese candidate for next major version

SemVer was originally defined for managing versions of software providing a public API, with the intent to improve component dependency management.

The numbering scheme is broadly used, including with adapted semantics for software without public API.