Hello Linux Geeksters. As you may know, the development for Ubuntu 15.04 Vivid Vervet has started in October, this year. Recently, Canonical has announced that Ubuntu 15.04 has switched to Kernel 3.18, which is the newest stable Kernel available.

For now, Ubuntu 15.04 is in its early development stages, it didn’t even reach the alpha stage, so the system is highly unstable for now. For now, there isn’t much information about the system, but most likely it will be still using a version of Unity 7 and X.org, while Unity 8 and Mir may be installable via third party repositories.
The first alpha version of Ubuntu 15.04 is scheduled for release on the 18th of December, while Ubuntu 15.04 Alpha 2 will become available on the 22rd of January.
The final version of Ubuntu 15.04 will be either running on an iteration of Kernel 3.18, or Kernel 3.19, if it gets release until the 5th of February, when Ubuntu 15.04 reaches Kernel freeze.
For now, Canonical is updating the kernels for Ubuntu 10.04 LTS, Ubuntu 12.04 LTS, Ubuntu 14.04 LTS and Ubuntu 15.04 and working at the Ubuntu 14.04.2 point release.