A colleague found the right override: https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/s3/S3BaseClientBuilder.html#requestChecksumCalculation(software.amazon.awssdk.core.checksums.RequestChecksumCalculation)
So, the fix is simple: Just add .requestChecksumCalculation(RequestChecksumCalculation.WHEN_REQUIRED)
to your S3Client.builder()
and it will work just as smoothly as before the update to AWS SDK >=2.30.0.