The KDE Plasma Workspaces code is still in a frozen LTS state until August 2015 while the KDE applications and libraries are marching ahead to KDE 4.14 this summer. The KDE 4.14 release is scheduled to come in four months, on 13 August.
Before the mid-August debut of KDE 4.14 there is the feature/API/dependency freeze on 25 June, the first and second betas in early July, the third beta and release candidate in late July, and the final tagging on 6 August.
KDE developers are still discussing whether KDE 4.14 will end up being the last Qt4-based KDE release or if there will be a KDE 4.15 release. Whatever release ends up being the last Qt4-based release will be preserved in a long-term support form. KDE Frameworks 5, Plasma 2, and the other next-generation KDE components are set to be released later in the year, hence the shift in focus to the newer platform.
The KDE 4.14 release schedule can be found via techbase.kde.org.