MARC Report 251 adds support for the changes introduced by–

MARC21 Update No. 26--Bibliographic
MARC21 Update No. 26--Authorities

–announced by LC on April 27, 2018.

In addition, MARC Report 251 updates its codelists to include changes added by the following:

• Additions to MARC Country and Geographic Area Codes Lists (April 19, 2018)

• Additions to Source Codes for Vocabularies, Rules, and Schemes (June 15, 2018)

• Additions to Source Codes for Vocabularies, Rules, and Schemes (May 25, 2018)

• Additions to Source Codes for Vocabularies, Rules, and Schemes (April 13, 2018)

• Additions to Source Codes for Vocabularies, Rules, and Schemes (March 9, 2018)

• Additions to Source Codes for Vocabularies, Rules, and Schemes (January 26, 2018)