ResolutionStarting with Parallels Plesk Panel version 10.4, Parallels will provide product updates in the following four tiers:
Testing version -- This option is available only if you have installed a testing build. We recommend that you use this version only for previewing and evaluation purposes because we do not provide technical support for such builds (even if they have since been upgraded to more stable builds). Avoid using this version in a production environment.
Pre-release version -- This version is fully featured, and previous versions successfully upgrade to it in testing. The quality of such version is eventually improved by updates. By selecting this version, you become the first to see the new features and will receive the latest updates.
Release version -- A release version has passed all quality tests. Minor stability issues are promptly fixed by updates. We recommend that you always upgrade Panel to release versions.
Stable version -- A stable version has received all updates, and a number of service providers have successfully used it for some time. When a version is considered stable, it no longer receives any updates.
The Parallels Plesk Panel administrator can switch between these versions on the page Tools & Settings > Update and Upgrade Settings as shown below: