Mailing the story:
Kubuntu LTS
The release schedule for KDE 4 is now clear, and it will be released during the development cycle of Kubuntu 8.04. Since KDE 4 is a major change to the platform, it is not currently at one of these natural rest points so would not be suitable for long term support. Instead, due to the very high interest, development efforts will be directed towards KDE 4 and releasing Kubuntu 8.04 with the option of using either KDE 3.5 or KDE 4.