In November 2020, OMB released M-21-07 "Completing the Transition to Internet Protocol version 6", which outlines milestones/requirements for federal agencies to meet for the transition to IPv6. This memorandum is publicly available at https://www.whitehouse.gov/wp-content/uploads/2020/11/M-21-07.pdf.
CMS has worked alongside HHS to develop a Department-wide IPv6 policy to which CMS will adhere. This policy has been published by HHS and is available at: https://www.hhs.gov/web/governance/digital-strategy/it-policy-archive/hhs-policy-transition-internet-protocol-version-6-ipv6.html.
For more information, or if you have questions regarding CMS’ implementation/migration to IPv6, please contact IPv6_Transition@cms.hhs.gov