The following documents the changes contained in the twenty-seventh update to the 1999 edition of MARC 21 Format for Authority Data.  Update No. 27 (November 2018) includes changes resulting from proposals that were considered by the MARC 21 community since the publication of Update No. 26 (April 2018).

New content designator:

Subfield code

$2  Number source (NR) in 055 (Library and Archives Canada Call Number)

Change in content designator definition:

Subfield code

$6  Linkage redescribed in Appendix A (Control Subfields).

See also:

Appendix F:  Format Change Lists