General availability: Azure Sphere OS version 21.09

Azure Sphere OS version 21.09 is now available in the **Retail** feed. This quality release includes bug fixes in the Azure Sphere OS; it does not include an updated SDK. If your devices are connected to the internet, they will receive the updated OS from the cloud. ### Updates to the Azure Sphere OS include * Upgraded Linux Kernel to 5.10.60. * Improvements to crash handling to prevent hangs. ### New and updated Gallery projects for 21.09 * [RS-485 real-time driver](https://github.com/Azure/azure-sphere-gallery/tree/main/RS485Driver) demonstrates how to use an M4F core on MT3620 to implement reliable RS-485 communication with inter-core communication to the high-level app on the A7 core. For more information on documentation updates, see [New and revised documentation in the 21.09 release](https://docs.microsoft.com/azure-sphere/product-overview/whats-new#new-and-revised-documentation-in-the-2109-release). For more information on Azure Sphere OS feeds and setting up an evaluation device group, see [Azure Sphere OS feeds](https://docs.microsoft.com/azure-sphere/deployment/deployment-microsoft-feeds) and [Set up devices for OS evaluation](https://docs.microsoft.com/azure-sphere/deployment/set-up-evaluation-device-group). For self-help technical inquiries, please visit [Microsoft Q&A](https://docs.microsoft.com/answers/search.html?c=&includeChildren=&f=&type=question+OR+idea+OR+kbentry+OR+answer+OR+topic+OR+user&redirect=search%2Fsearch&sort=relevance&q=azure%20sphere%20OS) or [Stack Overflow](https://stackoverflow.com/search?q=azuresphere&s=23550afd-6ece-47d5-a84f-2d0dc6fc9cf5&s=3b14b5b6-0179-4a03-ac51-bc826cc46fb1). If you require technical support and have a support plan, please submit a support ticket in [Microsoft Azure Support](https://ms.portal.azure.com/?quickstart=true&CAF=true#blade/Microsoft%5FAzure%5FSupport/HelpAndSupportBlade/overview) or work with your Microsoft Technical Account Manager. If you would like to purchase a support plan, please explore the [Azure support plans](https://aka.ms/azuresupport/). * Azure Sphere * Operating System * [ Azure Sphere](https://azure.microsoft.com/en-gb/services/azure-sphere/)