This article explains  Liferay's DXP docker image versioning format, image tag types and their implications. Liferay DXP docker images can be found on Docker Hub here.

Anatomy of an Image Version

{Liferay DXP Major/Minor Version}-{Liferay Release Type}-{Image Version}-{Build Time and Date}

Liferay DXP Major/Minor Version

For example 7.4.13. The 7.4 refers to the major version while the .13 refers to the minor.

Changes to the major Liferay version (e.g. "7.3.x" to "7.4.x") are major version changes that require portal schema version upgrade processes and module schema version upgrade processes using the DB Upgrade Tool.

Changes in the minor version (e.g. "7.4.10" to "7.4.13") are version changes in the Community Edition which contain portal schema version upgrade processes and module schema version upgrade processes using the DB Upgrade Tool.

Liferay Release Type

The part of the tag name that follows the Liferay major/minor version is the release type. In general changes in the release type are changes to Liferay on the same major version (i.e. changes to the patch level) and include bug fixes and  product improvements. These Updates contain required and optional module version schema upgrade processes (Upgrade Processes for Fix Pack in DXP 7.3 and Above). The format of this tag name part is following the naming conventions of the particular release type in subject.

Docker Image Version

The docker image version will have a major version, minor version, and patch version (d3.0.12).