Versioning - Amazon Simple Storage Service
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Versioning

If you enable versioning for a bucket, POST automatically generates a unique version ID for the object being added. Amazon S3 returns this ID in the response by using the x-amz-version-id response header.

If you suspend versioning for a bucket, Amazon S3 always uses null as the version ID of the object stored in a bucket.

For more information about returning the versioning state of a bucket, see GET Bucket (Versioning Status).

Amazon S3 is a distributed system. If you enable versioning for a bucket and Amazon S3 receives multiple write requests for the same object simultaneously, all versions of the object are stored.

To see sample requests that use versioning, see Sample Request.