The 8.x-1.x branch is now on Drupal.org https://www.drupal.org/project/serial/git-instructions
Drupal 8 port of the [Serial Field module] (https://www.drupal.org/project/serial). Related issue on Drupal.org.
The [Drupal Module Upgrader] (https://www.drupal.org/project/drupalmoduleupgrader) has been executed against the 7.x-1.x-dev release.
Using the issue tracker as a roadmap for the port.