From NCURA's e-Xtra Newsletter:
"We encourage everybody from graduate students to senior scientists to register for an ORCID account and link it to their eRA Commons personal profile. Starting October 1, 2019, ORCID identifiers will be required for individuals supported by institutional research training, career development, and other research education awards. xTrain appointments will not be accepted for agency review if potential appointees do not have an ORCID iD linked to their eRA personal profile. ORCID iDs will also be required for PD/PIs on individual fellowship and career development applications submitted for due dates on or after January 25, 2020.