These downloads include the latest supported release of the software, presently version 3.1.1, as well as archived releases which are no longer supported and, on occasion, release candidate versions.
They contain a full copy of all necessary components and don't require the destination PC to have an internet connection, though it is advantageous for licensing.
Release Candidate versions of the software have been fully tested in the lab but have not yet completed field trials. If you should decide to download and install the release candidate versions, you do so entirely at your own risk. No service level or support is available for release candidate versions of the software. A release candidate may not be released as a supported version.