By Adrian Turner, CDL Data Acquisitions

The "CDL Guidelines for Digital Objects, Version 2.0" (CDL GDO) has been updated to include specifications for use of the METS File <file> element.  You can find the updated version at .

The revision applies to Sections 2.1, 2.2.2, 3.1, and 3.2.4 only:

  • To support the orderly transmission and ingest of digital objects, the CDL recommends the inclusion of checksum (MD5, SHA-1, or CRC32) and byte size values in the METS File <file> element.  Note that this information is preferred, but not required.
  • The subheadings within Sections 2.1 and 3.1 have been relabeled, and are now consistently based on METS element names.

Please contact the CDL at if you have any questions.