This recommended update of KDE Frameworks 5 libs and Plasma5 provides the latest bugfix release 5.4.0.
The full announcement of the Plasma5 changes you can find here: https://www.kde.org/announcements/plasma-5.1.1.php
The full announcement of the KDE Frameworks 5 changes you can find here: https://www.kde.org/announcements/kde-frameworks-5.4.0.php