Check out this blog from Michael Young discussing upcoming security improvements revolving around TLS in the ArcGIS Platform, including insight into what's coming after the ArcGIS Online TLS updates coming in February.
2019 ArcGIS Transport Security Improvements
Take-away's include:
February 2019 – ArcGIS Online TLS 1.0 & 1.1 deprecation
Upcoming ArcGIS Enterprise 10.7 – TLS 1.0, 1.1, and HTTP disabled by default
June 2019 – ArcGIS Online HTTP deprecation + HSTS enforcement
And MORE!
--Randall
