All S3 clients must use part sizes between 5 MiB and 5 GiB.
AWS size limits for multipart parts are now enforced. Each part in a multipart upload must be between 5 MiB and 5 GiB. Only the last part can be smaller than 5 MiB (5,242,880 bytes).
Enhancements to S3 REST API support
The PUT Bucket tagging, GET Bucket tagging, and DELETE Bucket tagging operations are now supported. You can use these operations to add, retrieve, and delete a set of tags for a bucket. Cost allocation tags are not supported.
For newly created buckets, you no longer need to restrict object key names to meet performance best practices. For example, you can now use random values for the first four characters of object key names.
Configuring bucket notifications for the s3:ObjectRestore:Post event type is now supported.
You can now use DELETE Multiple Objects on a versioned bucket.
You can now use PUT, GET, and DELETE Bucket encryption requests to manage encryption for an existing S3 bucket.
A minor change was made to a field name for the Expiration parameter. This parameter is included in the response to a PUT Object, HEAD Object, or GET Object request if an expiration rule in the lifecycle configuration applies to a specific object. The field that indicates which expiration rule was matched was previously named rule_id. This field was renamed to rule-id to match the AWS implementation.
The Content-MD5 request header is now correctly supported.