VERIFIED SOLUTION i

Are the subkeywords CRIDCU, CRIDHU, CRIDMU, and CRIDPU required in MailStream Plus?

Product affected: MailStream Plus™, all versions, all platforms.
The new CRIDxx subkeywords are not required for MailStream Plus. 

CRIDCU populates SEG-1185 (Container Uniqueness Manager CRID) and can be on a RP INF, EP INF, or BATINF parameter.

CRIDHU populates SEG-1184 (Handling Unit Uniqueness Manager CRID) and can also be on a RP INF, EP INF, or BATINF parameter.

CRIDMU populates MPU-1130 (Move Update Supplier CRID) and can be on a PA INF, or RP INF parameter.

CRIDPU populates MPU-1131 (Piece Uniqueness Manager CRID) and can also be on a PA INF, or RP INF parameter.

Located here:
https://postalpro.usps.com/mnt/glusterfs/2018-12/USPS_Mail_dat_Tech_Spec.pdf
In the USPS's document...
      Postal Service Technical Specification
      Mail.dat
      Version 3
      Release 48
      January 13, 2019
...for all four fields it says "Currently not supported by PostalOne! "

Whether the USPS will require them in the future for a specific Mailer's mailings would have to be checked with the USPS. The PostalOne! HelpDesk number is 800-522-9085, or email postalone@email.usps.gov
UPDATED:  May 15, 2019