The CMS New Medicare Card (NMC) web page at https://www.medicare.gov/newcard/ keeps an ongoing tally of NMC mailings. It shows that mailings are now underway for California, Oregon, and Alaska, but have not yet started for other Network 16 states. The page also includes a sample of the new card, important information about what a patient should do when they receive one in the mail, and important tips on avoiding Medicare scams.
For providers, CMS has also published information on when a Medicare Beneficiary Identifier (MBI, which replaces the HICN on the card) can change, and what to do when it does. Find a summary at https://www.cms.gov/Outreach-and-Education/Outreach/FFSProvPartProg/Provider-Partnership-Email-Archive-Items/2018-07-05-eNews.html?DLPage=1&DLEntries=10&DLSort=0&DLSortDir=descending#_Toc518370286.