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Azure IoT SDK
An Azure software development kit that facilitates building applications that connect to Azure IoT services.
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Hello @那須 昭吾 ,
yes, Microsoft is moving over to another certificate to secure IoT Hub device connectivity using TLS.
This has no impact on the device identities for any x509 cert you use to identify a device (next to PTM or symmetric key). It's just about securing the transport of data.
Please check that blog post. There, you read about how to check your (test) device and how to validate:
Also, check the comments at the bottom of the blog where the Azure IoT team answers in-depth questions.