What does S3 Policy Version mean?

Question

What does S3 Policy Version mean?

{
   "Version": "2008-10-17",
   "Statement": [{
                    "Sid": "AllowPublicRead",
                    "Effect": "Allow",
                    "Principal": { "AWS": "*" },
                    "Action": ["s3:GetObject"],
                    "Resource": ["arn:aws:s3:::bucket/*" ]
                }]
}

It is automatically added to the policy when we edit the policy.

Answer 1

It used to version the policy schema or metadata - the set of attributes you can use in your policy.

If Amazon will issue an updated policy with additional fields the version will be increased.