Some alternative (unofficial) Russian localization teams modify the automatic update procedure to download WordPress core packages from their own hosts. The problem is that they systematically fail to deliver updates on time (even security updates) and currently provide no visible support for their releases.
This plugin allows you to update any outdated Russian WordPress package to the latest release from ru.wordpress.org.
You can safely remove the plugin after the update.
Thanks to AlexPTS for the idea.
This plugin is available for download to be used on your WordPress self-hosted installation.