Upcoming Major version change and breaking changes

[timtay-microsoft]

Hi all,

The Java SDK team here at Microsoft is planning on putting out a major version update to the packages in this library that will include some breaking changes. This thread will call out what the specific changes will be, why we feel these changes are needed, and will allow us to solicit general feedback from users about potential other changes they'd like to see.

To start, here are the breaking changes that we are already committed to making:

• Read trusted certificates from the device rather than store them within the SDK itself
  • This is partially motivated by wanting to align with the other IoT hub language SDKs, but mostly motivated by wanting to decouple SDK versions from a trusted certificate since IoT hub will be changing its root certificate in the near future. You can read more about this transition here
  • This change may break users if they do not already have the Baltimore CyberTrust Root certificate installed on their device. Users can find this certificate on Digicert's official website here. Users are also advised to install the DigiCert Global Root G2 certificate listed on the same website since IoT hub will be transitioning to that as its root certificate as mentioned in the bullet point above. Note that both of these trusted certificates are commonly installed on devices already, so this change may not impact users.
• Remove the Bouncycastle dependency from our SDK's dependency lists
  • This is a rather large dependency, and the SDK was only using it for some basic certificate parsing. We'll be putting this certificate parsing logic in our samples rather than in our SDK.
• Remove the Azure Storage dependency from the IoT hub device SDK dependency list
  • This dependency was part of a now deprecated file upload API in the IoT hub device SDK. Users will still be able to get Azure Storage SAS URIs for uploading files from their IoT devices, but this SDK will no longer handle the actual file upload step. More details can be seen here.
  • Users who were using the deprecated file upload API are advised to now follow the pattern demonstrated in our file upload sample
• Remove the declared thrown exceptions from methods where the exception is no longer thrown
  • Many constructors such as this one declare that they throw a particular exception, but they either no longer throw that exception, or never threw that exception in the first place. Since this led to some confusion among users, we will use this major version rev to clean these up.
• Remove the currently deprecated APIs from all packages
  • Over the years, we've deprecated many constructors and some clients, and now is a good opportunity to finally remove them to simplify the SDK. All currently deprecated APIs list the suggested API that users should migrate to.

As a team, we have larger plans for reworking these packages in the future, so this smaller effort is only aimed at making the current packages smaller, easier to maintain, and more future-proof.

That said, if you have any questions/comments/concerns about the changes listed above, or have any suggestions for similar changes you'd like to see in this SDK, please leave a comment in this thread.