How to enforce a minimum TLS version
To ensure managed assets use no lower than a minimum version of TLS for network communication, you can set the minimum TLS version allowed. This setting is located in the Global Asset Policy.
To enforce a minimum TLS version across HTTPS and asset-to-asset communication:
1. Starting in the dashboard, click System > Settings.
2. In the System Settings pain, click Global Asset Policy.
3. Set Minimum TLS version allowed to a minimum version of TLS.
Note: All communication must negotiate into using the minimum version of TLS or higher. If it cannot, then no network connection is made. This includes REST API requests and user access to OMS and Apex through a web browser.
You might be prompted to confirm your choice depending on the TLS version you select.
4. Click the accept icon .
 
Assets now prohibit network connections that use a TLS version lower than the minimum TLS version allowed.