As a follow up to parent issue, field definition updates should be done with help of "entity.definition_update_manager" and "entity_field.manager" services that are in Drupal core since 8.2 at least.
That is why update 8401 is not complete and needs the update from 8402, that is in the attached patch.
Needs work
4.0
Flag core
The patch will have to be re-rolled with new suggestions/changes described in the comments in the issue.
Not all content is available!
It's likely this issue predates Contrib.social: some issue and comment data are missing.
The latest dev still doesn't have that update listed, so I guess yes, it is still relevant.