It should be fairly easy to upgrade compatible APIs server side from reading the AWS docs. All that needs doing is to accept and ignore the new checksum header. I also expect that taking advantage of the checksum would be reasonable, a CRC32 isn't that hard.

https://aws.amazon.com/blogs/aws/introducing-default-data-in...

Seconded - it's also unnecessarily creative overvalidation on the part of the devs at those joints.