Updates several existing field options in one call, inside a single transaction: if any option fails validation the whole request is rolled back. Every entry must carry the id of the field option to update and its field property (the id of the custom field it belongs to). Entries without a field property, whose field id does not exist, or whose field the API user cannot access, are silently skipped and missing from the response; the response's fieldOptions array holds only the options that were actually updated. Every update rewrites an option's label to match its value unless the entry also changes the label to new text, so labels that differ from their values must be updated, not merely re-sent, to survive. 404 if an entry's id does not match an existing field option.