https://www.bleepingcomputer.com/news/google/a-google-drive-security-update-will-break-some-of-your-shared-links/

An upcoming security update for Google Drive will increase the security of your shared documents but likely break many of your shared links.

Yesterday, Google began emailing Google Workspace admins about a new security update for Google Drive rolling out on September 13th, 2021, to make file sharing more secure.