Azure Sphere OS version 21.04 is now available for evaluation
Published Apr 15 2021 03:30 PM 1,480 Views
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Azure Sphere OS version 21.04 is now available for evaluation in the Retail Eval feed. The retail evaluation period provides 14 days for backwards compatibility testing. During this time, please verify that your applications and devices operate properly with this release before it is deployed broadly via the Retail feed. The Retail feed will continue to deliver OS version 21.03 until we publish 21.04 in two weeks. For more information on retail evaluation see our blog post, The most important testing you'll do: Azure Sphere Retail Evaluation.


This evaluation release includes an OS update only; it does not include an updated SDK.


Notes about this release


  • Areas of special focus for compatibility testing with 21.04 should include apps and functionality utilizing:
    • Any wolfSSL calls, as it has been upgraded to version 4.7.
    • Wi-Fi connectivity as the background scanning process had been upgraded.
  • 21.04 includes updates to mitigate against the following CEVs:
    • CVE-2021-28460
    • CVE-2021-22876
    • CVE-2021-22890
  • RF tools version 21.01 is compatible with OS version 21.04.


For more information on Azure Sphere OS feeds and setting up an evaluation device group, see Azure Sphere OS feeds and Set up devices for OS evaluation.


For self-help technical inquiries, please visit Microsoft Q&A or Stack Overflow. If you require technical support and have a support plan, please submit a support ticket in Microsoft Azure Support or work with your Microsoft Technical Account Manager. If you would like to purchase a support plan, please explore the Azure support plans.

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Last update:
‎Apr 15 2021 03:23 PM
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