Require TLS 1.2 for HTTPS Connections in Communities and Sites (Critical Update, Enforced)
Where: This change applies to communities and sites accessed through Lightning Experience and Salesforce Classic in Essentials, Enterprise, Performance, Unlimited, and Developer editions.
When: This critical update is enforced for production orgs on October 25, 2019. Communities enabled after this date require TLS 1.2 by default. For other implementation dates, see the knowledge article, Salesforce Disabling TLS 1.1.
How: We recommend that you test this update in a sandbox or Developer Edition org to verify end-to-end compatibility before enabling it in your production org. We also recommend that you inform your community users about this upcoming change and encourage them to upgrade to browsers that support TLS 1.2.
To activate this critical update before October 25, 2019, from Setup, enter Critical Updates in the Quick Find box, then select Critical Updates. For Require TLS 1.2 for HTTPS Connections for Communities and Sites, click Activate.