Lightning uses a three-part semantic versioning nomenclature within the constraints of drupal.org's current capabilities. See this drupal.org issue for the latest.
The three parts of our versioning system are MAJOR.FEATURE.SPRINT. However, due to the current constraints of drupal.org, there is no separator between the FEATURE and SPRINT digits. This also limits Lightning to ten sprint releases before releasing a new feature.
Given the following tag: 8.x-1.23:
| 8 | Major version of Drupal Core |
| x | Works with any minor version of the indicated Major version of Drupal core |
| 1 | Major version of Lightning |
| 2 | Feature release of Lightning |
| 3 | Sprint release between feature releases |
Lightning typically makes a sprint release every four weeks. We'll also use
sprint releases to package new minor releases of Drupal Core with Lightning as
they become available. Drupal Packagist does not allow patch release specificity
for Drupal core. That is, even if Lightning were to specify drupal/core:8.0.5,
Drupal Packagist would convert that to drupal/core:~8.0.5 (note the tilde). As
a result, Lightning will not make releases for Drupal Core Patch Releases.
Lightning release tags are synchronized with releases of Lightning's Composer-based installer. Since the installer is not distributed on drupal.org, Lightning version 8.x-1.23 corresponds with installer version 8.1.2-patch3, and so on.