I am experiencing difficulties during CiviCRM upgrade from 4.7.14 to 4.7.31 or 5.1, namely, fields like contact.birth_date get broken. (More: DB Error after upgrading 4.7.x to 5.1 (Drupal))
I have noticed that during CiviCRM version update, there is a process of sequential updates that seem to also include database updates.
I wonder, if it is possible to export full database and re-import it in a newer version fresh CiviCRM installation?