OCLC has instituted changes to enable the use of OCLC control numbers above 99,999,999. As a result, on November 12, all bibliographic records output from OCLC systems will contain the OCLC number from field 001 in field 035. Subfield $a will include the OCLC number as a variable-length numeric string with no leading zeros and preceded by (OCoLC). Subfield $z will include the OCLC number from field 019 for cross-reference records which have been deleted and merged with the present record. Subfield $z is repeatable and will not be present in every record. The OCLC control number will continue to be present in field 001.

In addition, the transaction codes for the update and delete actions that were previously stored in Leader byte 22 will no longer be stored there. Leader byte 22 will always contain value 0 (zero). The transaction codes will continue to be present in field 994. Previously these codes were in both places. These changes may affect the way you handle OCLC records in your local system. If you have concerns about how your local system will handle these changes in coding, please contact your local system vendor. OCLC began notifying local system vendors of its plan to make these changes earlier this year.

These changes will appear in records delivered either via MARC Subscription on PSWeb or via export from CatExpress. See Technical Bulletin 253 — www.oclc.org/support/documentation/worldcat/tb/253/default.htm — for more information.