The Product Owner has the sole authority on putting the work of the Scrum Team at the end of a Sprint into the hands of users. This means that at the end of a Sprint, after the Sprint Review has occurred, the Product Owner considers the state of the Product (features, quality, performance, etc.) and the state of the business/market, and decides if the product should be sent out. In an IT or web environment, this means deployment. For other types of software this might be live updates or sending out DVDs to customers. There should be no other individuals who have the authority to do extra releases without the Product Owners approval, nor should there be anyone who can stop a release from going out if the Product Owner makes that decision. If the Product Owner has this authority, it can create a high level of efficiency in addressing the needs of the business or the needs of the market. If the Product Owner does not have this authority, then it undermines their authority over the ordering of the Product Backlog (since that ordering becomes meaningless) and it undermines the broader organization’s ability to hold the Product Owner accountable for results.
To learn more about Product Owners, visit the Scrum Team Assessment.