Require Secure HTTPS Connections was an update in Spring ’20 and was enforced in production orgs on May 1, 2020. As part of updates related to Google Chrome’s SameSite cookie changes, HTTPS connections are required to access Salesforce. HTTP connections are no longer permitted. This update enabled the Require secure connections (HTTPS) setting on the Session Settings Setup page and prevented it from being disabled. The Require secure connections (HTTPS) for all third-party domains setting isn’t affected by this update.
Where: This change applies to Lightning Experience, Salesforce Classic, and all versions of the Salesforce app in all editions.
When: This update was activated automatically on May 1, 2020 in production orgs.
To view this update, from Setup, in the Quick Find box, enter Critical Updates, then select Critical Updates. For Require Secure HTTPS Connections, click Review.