For a custom base image, Snyk recommends upgrading the image to the latest available version from the pool of images that have been imported as Projects, marked as custom base images and are enabled for recommendations. See Enable CBIR.
To determine which is the latest version, Snyk uses a versioning schema that allows comparing image tags.
Managing the versioning schema for images imported to projects for a repository can be done either from the Web UI or the Snyk REST API.
Snyk supports the below versioning schemas.
Semantic Versioning (SemVer)
This schema adheres to the Semantic Versioning Specification (SemVer).
In the below example, when Snyk scans the images and marks them as custom base images in the order shown, the SemVer logic is:
Snyk recommends the second image, as it is the newest image based on the semantic versioning of the tag.
The following commonly used examples are not supported SemVer tags:
This versioning schema allows you to manually set a single image as a recommendation.
When selecting an image, any other previously selected images are automatically unselected.
Custom versioning schema
If none of the above schemas match your requirements, you may create a custom versioning schema. For more information, see Custom Versioning Schema for custom base images.