Microsoft has just released a new version of the Azure Sphere OS: https://techcommunity.microsoft.com/t5/internet-of-things/azure-sphere-update-20-01-is-now-available/ba-p/1170872
The update includes security improvements as well as changes for servicing devices in field.

You can also find introductory information on Azure Sphere, a very interesting security and connectivity IOT solution, in our latest Wechsler Consulting Cloud News Clip!

Update 26.02.2020:
As announced this Monday in Nuremberg, at the Azure IOT in Action event, Azure Sphere solution is now generally available: https://azure.microsoft.com/en-us/services/azure-sphere/ as well as on the Security Blog https://azure.microsoft.com/de-de/blog/a-secure-foundation-for-iot-azure-sphere-now-generally-available/