4. (Advanced) Use Alternative Package Repositories
By default, Plesk Installer fetches the packages required for Plesk installation or upgrade from the standard repository of your operating system. However, if you want to have a latest package version that is not yet available in the standard repository, you can install this version from an alternative repository. To do this, enable this repository on your server. The instructions on enabling alternative repositories are available on the websites of these repositories.
If you enable alternative repositories in your system, Plesk Installer uses the latest versions of packages it finds in all available repositories when installing or upgrading Plesk. For example, if Plesk updates contains MySQL v.5.5.30, and another repository enabled on your server (for example, IUS) contains MySQL v.5.5.34, the most current version (5.5.34) will be installed.
Important: If you upgraded to Plesk 12.5 from an earlier version and configured alternative repositories according to the instructions in previous version of this guide, we strongly recommend that you revert all changes you made according to this instruction and use alternative repositories according to this document.