copySourceIfUnmodifiedSince

Copies the object if it hasn't been modified since the specified time.

If both of the x-amz-copy-source-if-match and x-amz-copy-source-if-unmodified-since headers are present in the request as follows:

x-amz-copy-source-if-match condition evaluates to true, and;

x-amz-copy-source-if-unmodified-since condition evaluates to false;

Amazon S3 returns 200 OK and copies the data.