Greetings CoC Providers: 
The General Services Administration will begin phasing out using the DUNS number, and will begin to use a Unique Entity Identifier (UEI) by December 2020. This will affect you doing business with the federal government, and applying for HUD-Continuum of Care, federal funding. 
Please see the link below to review the new process regarding the UEI:
https://www.gsa.gov/about-us/organization/federal-acquisition-service/office-of-systems-management/integrated-award-environment-iae/iae-information-kit/unique-entity-identifier-update
Further inquiries may be directed to entityvalidation@gsa.gov.