Mandatory Modification definition in Computer Security terms:
Definition(s): A change to a COMSEC end-item, which the National Security Agency (NSA) requires to be completed and reported by a specified date. See optional modification.
Source(s): CNSSI 4009-2015 (Adapted from NSA/CSS Manual Number 3-16 (COMSEC))
Synonym(s): Optional Modification
National Security Agency (NSA)-approved modification not required for universal implementation by all holders of a COMSEC end-item. This class of modification requires all of the engineering/doctrinal control of mandatory modification but is usually not related to security, safety, TEMPEST, or reliability. See mandatory modification (MAN).
Source(s): CNSSI 4009-2015
reference: CSRC Glossary