Red Hat Quay is regularly released, containing new features, bug fixes, and software updates. We highly recommend deploying the latest version of Red Hat Quay.
For Red Hat Quay documentation, you should know that:
Documentation is versioned along with each major release
The latest Red Hat Quay documentation is available from the Red Hat Quay Documentation page
Prior to version 2.9.2, the product was referred to as Quay Enterprise
Documentation versions prior to 2.9.2 are archived on the CoreOS site
Red Hat Quay, version 3 is the latest major version.