Announcement: S3 default integrity change

[aBurmeseDev]

In AWS SDK for PHP v3.337.0, we released changes to the S3 client that adopts new default integrity protections. For more information on default integrity behavior, please refer to the official SDK documentation. In SDK releases from this version on, clients default to enabling an additional checksum on all Put calls and enabling validation on Get calls.

You can disable default integrity protections for S3. We do not recommend this because checksums are important to S3 integrity posture. Integrity protections can be disabled by setting the config flag to WHEN_REQUIRED, or by using the related AWS shared config file settings or environment variables.

Disclaimer: the AWS SDKs and CLI are designed for usage with official AWS services. We may introduce and enable new features by default, such as these new default integrity protections, prior to them being supported or otherwise handled by third-party service implementations. You can disable the new behavior with the WHEN_REQUIRED value for the request_checksum_calculation and response_checksum_validation configuration options covered in Data Integrity Protections for Amazon S3.

[jelninos]

Related to this announcement, it seems that the client no longer transmits the "Content-MD5" header for deletion.
But the API documentation still says it's required for all Multi-Object Delete requests... who's right?
I described this issue here:
#3127

Thanks !