Canonical and the Kubuntu team decided that, due to the delayed release of KDE 4, the upcoming release of Kubuntu, 8.04, will not be a long term support release.
Periodically, Ubuntu, Kubuntu and other Ubuntu variants from Canonical launch a LTS release (the version is supported for three years on the desktop and five years on the server). Canonical and the Kubuntu team have decided not to tag Kubuntu 8.04 as LTS, because KDE 4 will be released shortly before the distro. Incorporating KDE 4 in Kubuntu would be premature, and could cause instability to the system.
It seems to be a solution to this, according to an announcement on the Kubuntu mailing list. This would offer the user the possibility to choose between KDE 3.5.8 and KDE 4. But it will still not be LTS, breaking the standard schedule of the long term support editions.
Announcement : https://lists.ubuntu.com/archives/ku…er/002066.html