Packages for the release of KDE Applications 15.04 are available for Kubuntu 15.04. You can get it from the Kubuntu Backports PPA.
Bugs in the packaging should be reported to kubuntu-ppa on Launchpad. Bugs in the software to KDE.
To update, use the Software Repository Guide to add the following repository to your software sources list:
ppa:kubuntu-ppa/backports