ArcGIS Online uses TLS to communicate with the rest of the ArcGIS Platform. Today, it can use a few different versions (1.0, 1.1 and 1.2). But from February 2019, for security reasons, ArcGIS Online will be updated so that it only supports TLS version 1.2.
When this happens, every client that communicates with ArcGIS Online must also support TLS version 1.2. If they don’t, functionality that uses ArcGIS Online, such as the Living Atlas, Feature Services, Routing or Basemaps, will no longer work.
What you need to do
This page will guide you through the preparations you need to make on a product-by-product basis. Not every product needs patching, but it’s important to check everything you use.
If you’re a LocatorHub user, you’ll also need to check out this blog post.
If you follow the guidance in these links before the February update, everything will continue to work with no interruptions.