How I migrated Drupal 6 (with Biblio module) to Drupal 8 (with Bibcite module)
I got the task of upgrading an old Drupal 6 webpage to a newer version. We
decided to skip Drupal 7 and go directly for Drupal 8 with the new bibcite
module (although it is still at 1.0-alpha7 at the time of this writing).
Upgrading most of the content of Drupal 6 to Drupal 8 worked rather fine, with the exception of the Views which have to be migrated separately. Migrating the content of the biblio to bibcite was quite a task though. In this text, I will report how I did the transition.
One of the biggest hurdles was, that the migration would split the publications into two separate entitys. In Drupal 6, there was a "Biblio" content type, which had a "biblio" field with all the bibliographic sub-fields. And there were a fewer custom fields (via CCK), e.g. a teaser image and some node references to projects (which were a separate content type).
After the migration, the publications are a separate entity type (Content -> Biblio