Leica Zeno 20 GPS not compatible with TLS 1.2, preventing ArcGIS Collector from working

Description

The Leica Zeno 20 GPS no longer allows sign-in or connecting to services in the ArcGIS Collector app following the TLS 1.2 ArcGIS Online update on April 16, 2019.

Cause

As of April 16, 2019, ArcGIS Online services only accepts connections using TLS 1.2. For more information, please see: Important Updates for the ArcGIS Platform and Transport Layer Security (TLS) Protocol Support

Solution or Workaround

• Customer Managed Proxy - If your organization has a proxy for HTTP/HTTPS traffic, simply go to the Zeno wireless settings and enter your proxy configuration information. By passing through a TLS 1.2 proxy, your connectivity to ArcGIS Online is via TLS 1.2 and it will work.  If your organization’s proxy public certificate is not already on the Zeno device, you will must add it as a trusted certificate.  This configuration has been successfully tested using a Squid proxy, and other TLS 1.2 proxies work in a similar capacity.  Because proxies can be vulnerable if not locked down appropriately, Esri is not distributing generalized proxy setup guidance, if using a proxy, Esri strongly recommends having your organization's information systems team fully manage it.
• ArcGIS Enterprise - If your organization already has ArcGIS Enterprise available, you can collect and store your information there instead of ArcGIS Online. While the current release of ArcGIS Enterprise only enables TLS 1.2 by default, ArcGIS Enterprise can be configured to use TLS 1.0 to support older Zeno Collector devices. 
• Leica Managed Proxy – Esri has provided documentation to Leica for configuring a proxy to support relaying HTTPS traffic to ArcGIS Online via TLS 1.2. Leica is looking at establishing such a proxy for customers who do not have their own proxy system. 
• External Receiver – As of April 26, 2019, Leica has a new Zeno Connect version available that enables this option. Customers can install ArcGIS Collector on current technology phones and then use the Zeno device to obtain centimeter-level GPS readings. To do this, one must first configure the Zeno device to be able to share readings via Bluetooth, then on the phone with Collector, choose the add the receiver option, and select the Zeno device.
• Zeno Mobile – Temporary licenses may be made available for this by Leica for your organization. If desired, please reach out to Leica directly for this  workaround.

For further assistance on these solutions, please reach out to Leica Support:
Email: gis.support@leicaus.com
Phone: 1-800-327-4773
Leica Geosystems Website: https://leica-geosystems.com