The addendum consists of changes to the MARC 21 Format for Authority Data resulting from revised decisions made regarding the outcome of MARC Proposal No. 2019-01, which came about after the publication of Update No. 28 (May 2019).  A full accounting of those changes can be found in the STATUS/COMMENTS section at the head of the proposal.

New content designator:

Subfield code

$7  Access status (NR) in 856 (Electronic Location and Access)

See also:

Appendix F:  Format Change Lists