The update feature is a package that is included in CampaignChain by default and can also be used independently from CampaignChain as a regular Symfony bundle.
The update package offers you the ability to include update routines in multiple separate CampaignChain modules or Symfony bundles. Essentially, it extends the DoctrineMigrationsBundle.
Documentation on how to install and use this bundle is available in the CampaignChain Documentation.