Backports is not enabled by default, but is included in the standard /etc/apt/sources.list. You may need to enable it. The repository you want to enable looks like:

deb-src http://archive.ubuntu.com/ubuntu/ jaunty-backports main restricted universe multiverse

Add this repository and do a full upgrade:

deb http://ppa.launchpad.net/kubuntu-ppa/ppa/ubuntu jaunty main

To install it add this line to your software sources.

deb http://ppa.launchpad.net/kubuntu-ppa/ppa/ubuntu jaunty main

It is strongly recommended that you verify the integrity of these packages by installing the archive’s GPG key. You may do this by saving the PUBLIC KEY BLOCK available from this page to a file and importing it from the authentication tab in KPackageKit’s software sources window.

Then refresh and do a full upgrade.

Jaunty (current development release)

Packages for Jaunty (current development release) are available. If you use Jaunty you will be able to upgrade as normal.

8.10 (Intrepid)

Packages for Kubuntu 8.10 can be installed by following the instructions below.

Note: These packages are not supported by Canonical; for a stable system it is not recommended to upgrade. KDE 4.2 will be officially supported as part of Kubuntu 9.04 being released April 23rd 2009.

Instructions

The updated packages for Kubuntu 8.10 are in the kubuntu-members-kde4 PPA. To update to KDE 4.2, please follow these instructions:

1. Remove the koffice-data-kde4 package if you have it installed. The current koffice2 packages in the kubuntu-members-kde4 PPA are incompatible with the KDE 4.2 packages since they try to install icons to the same locations.
2. Follow the Kubuntu Repository Guide to enable Recommended Updates and Unsupported Updates.
3. In Third Party Software add:
   deb http://ppa.launchpad.net/kubuntu-members-kde4/ppa/ubuntu intrepid main
4. Old Plasma packages are not compatible with KDE 4.2, you should uninstall any plasmoids.
5. You can now update any existing KDE 4 installation to 4.2 with Full Upgrade in the package manager, or using the Adept Updater tool in your system tray.
6. Now log out. When you log in you will have KDE 4.2. Enjoy.

Notes

KDE 4.2.2 uses Akonadi which will install MySQL. The MySQL packages in intrepid will ask for a password, you can set this to anything you like.

Digikam will not install alongside these packages due to conflicting library versions.

Bugs

If you come across any issue which may be packaging related, it is recommended that you join the Kubuntu IRC channel (#kubuntu on irc.freenode.net) and query those in the channel for assistance.

Thanks to Steve, Jonathan, Nathan, Roderick and awen for these packages.

If you want to see your name above, then join the Kubuntu Team.
More information is available in the Kubuntu Wiki.

For more information about the release itself, please see the Release Announcement

Jaunty (current development release)

Packages for Jaunty (current development release) are available. If you use Jaunty you will be able to upgrade as normal.

8.10 (Intrepid)

Packages for Kubuntu 8.10 can be installed by following the instructions below. If you installed KDE 4.2 Beta or RC you can merely update your existing installation.

Note: These packages are not supported by Canonical; for a stable system it is not recommended to upgrade. KDE 4.2 will be officially supported as part of Kubuntu 9.04 being released April 23rd 2009.

Instructions

The updated packages for Kubuntu 8.10 are in Unsupported Updates (backports). To update to KDE 4.2, please follow these instructions:

1. Remove the koffice-data-kde4 package if you have it installed. The current koffice2 packages in the kubuntu-members-kde4 PPA are incompatible with the KDE 4.2 packages since they try to install icons to the same locations.
2. Follow the Kubuntu Repository Guide to enable Recommended Updates and Unsupported Updates.
3. Old Plasma packages are not compatible with KDE 4.2, you should uninstall any plasmoids.
4. You can now update any existing KDE 4 installation to 4.2 with Full Upgrade in the package manager, or using the Adept Updater tool in your system tray.
5. Now log out. When you log in you will have KDE 4.2. Enjoy.

Notes

KDE 4.2 uses Akonadi which will install MySQL. The MySQL packages in intrepid will ask for a password, you can set this to anything you like.

Digikam will not install alongside these packages due to conflicting library versions.

Bugs

If you come across any issue which may be packaging related, it is recommended that you join the Kubuntu IRC channel (#kubuntu on irc.freenode.net) and query those in the channel for assistance.

Thanks to Harald “apachelogger” Sitter, Jonathan Riddell, Jonathan Thomas (aka JontheEchidna), Scott “ScottK” Kitterman and Steve Stalcup (aka vorian), Nathan Handler, Richard “Arby” Birnie and Roderick Greening for preparing and uploading these packages.

If you want to see your name above, then join the Kubuntu Team.
More information is available in the Kubuntu Wiki

Notes

This is a beta quality release and may yet prove to be unstable at times. This release will allow you to follow closely with what is going on in the KDE 4.2 development branch. Some of your plasmoids from KDE 4.1 may be incompatible with KDE 4.2 (and will be removed during the upgrade).

For more information about the release itself, please see the Release Announcement

Jaunty

Packages for the development Jaunty release are available. If you use Jaunty you will be able to upgrade as normal. Note that due to the holidays, the red tape needed to include libmsn in main has not been cleared yet. MSN support for Kopete will go in to Jaunty before it is released, however.

8.10 (Intrepid)

Packages for (K)Ubuntu 8.10 can be installed by following the instructions below. If you installed KDE 4.1 Beta2 you can merely update your existing installation.

Instructions

The updated packages for Kubuntu 8.10 are located in the Kubuntu Experimental Software Personal Package Archive (PPA) repository. To update to KDE 4.1.96 (4.2 RC 1), please follow these instructions:

1. Remove the koffice-data-kde4 package if you have it installed. The current koffice2 packages in the kubuntu-members-kde4 PPA are incompatible with the KDE 4.2 packages since they try to install icons to the same locations.
2. Follow the Kubuntu Repository Guide to enable Recommended Updates and add the following to your ‘Third-Party Software’ tab:
   deb http://ppa.launchpad.net/kubuntu-experimental/ubuntu intrepid main
3. You can now update any existing KDE 4 installation to the most recent version using the Adept Updater tool in your system tray.
4. Now log out and press Alt + E to restart X. When you log in you will have KDE 4.2 Release Candidate 1. Enjoy.

Bugs

There probably will at least a few bugs with this release and it is recommended that you do not file bug reports against the packages in this release. If you come across any issue which may be packaging related, it is recommended that you join the Kubuntu IRC channel (#kubuntu on irc.freenode.net) and query those in the channel for assistance.

Thanks to Harald “apachelogger” Sitter, Jonathan Riddell, Jonathan Thomas (aka JontheEchidna), Scott “ScottK” Kitterman and Steve Stalcup (aka vorian) for preparing and uploading these packages. Big thanks go to Nathan Handler “nhandler”, the newest Kubuntu ninja.

If you want to see your name above, then join the Kubuntu Team.
More information is available in the Kubuntu Wiki

Notes

This is a beta quality release and may yet prove to be unstable at times. This release will allow you to follow closely with what is going on in the KDE 4.2 development branch. Some of your plasmoids from KDE 4.1 may be incompatible with KDE 4.2 (and will be removed during the upgrade). The MSN plugin is now available for Kopete in the Intrepid packages.

For more information about the release itself, please see the Release Announcement

Jaunty

Packages for the development Jaunty release are available. If you use Jaunty you will be able to upgrade as normal.

8.10 (Intrepid)

Packages for (K)Ubuntu 8.10 can be installed by following the instructions below. If you installed KDE 4.1 beta1 you can merely update your existing installation.

Instructions

The updated packages for Kubuntu 8.10 are located in the Kubuntu Experimental Software Personal Package Archive (PPA) repository. To update to KDE 4.1.85 (4.2 beta 2), please follow these instructions:

1. Remove the koffice-data-kde4 package if you have it installed. The current koffice2 packages in the kubuntu-members-kde4 PPA are incompatible with the KDE 4.2 packages since they try to install icons to the same locations.
2. Follow the Kubuntu Repository Guide to enable Recommended Updates and add the following to your ‘Third-Party Software’ tab:
   deb http://ppa.launchpad.net/kubuntu-experimental/ubuntu intrepid main
3. You can now update any existing KDE 4 installation to the most recent version using the Adept Updater tool in your system tray.
4. Now log out and press Alt + E to restart X. When you log in you will have KDE 4.2 Beta 2. Enjoy.

Bugs

There probably will be many bugs with this release and it is recommended that you do not file bug reports against the packages in this release. If you come across any issue which may be packaging related, it is recommended that you join the Kubuntu IRC channel (#kubuntu on irc.freenode.net) and query those in the channel for assistance.

Thanks to Richard “Arby” Birnie, Harald “apachelogger” Sitter, Guillaume “smarter” Martres, Jonathan Thomas (aka JontheEchidna), Roderick “rgreening” Greening, Scott “ScottK” Kitterman and Steve Stalcup (aka vorian) for preparing and uploading these packages.

If you want to see your name above, then join the Kubuntu Team.
More information is available in the Kubuntu Wiki

Notes

This is a beta quality release and may yet prove to be unstable at times. This release will allow you to follow closely with what is going on in the KDE 4.2 development branch. Some of your plasmoids from KDE 4.1 may be incompatible with KDE 4.2 (and will be removed during the upgrade). Also, if you absolutely need MSN support in Kopete you probably don’t want to upgrade, as the MSN protocol is temporarily unavailable while we package new libraries needed for the rewritten MSN plugin.

For more information about the release itself, please see the Release Announcement

Instructions

The updated packages for Kubuntu 8.10 are located in the Kubuntu Experimental Software Personal Package Archive (PPA) repository. To update to KDE 4.1.80 (4.2 beta1), please follow these instructions:

1. Remove the koffice-data-kde4 package. The current koffice2 packages are incompatible with the KDE 4.2 packages since they try to install icons to the same places.
2. Follow the Kubuntu Repository Guide to enable Recommended Updates and add the following to your ‘Third-Party Software’ tab:
   deb http://ppa.launchpad.net/kubuntu-experimental/ubuntu intrepid main
3. You can now update any existing KDE 4 installation to the most recent version using the Adept Updater tool in your system tray.
4. Now log out and press Alt + E to restart X. When you log in you will have KDE 4.2 Beta 1. Enjoy.

Bugs

There probably will be many bugs with this release and it is recommended that you do not file bug reports against the packages in this release. If you come across any issue which may be packaging related, it is recommended that you join the Kubuntu IRC channel (#kubuntu on irc.freenode.net) and query those in the channel for assistance.

Thanks to Richard “Arby” Birnie, Harald “apachelogger” Sitter, Jonathan Thomas (aka JontheEchidna), Michael “NCommander” Casadevall and Steve Stalcup (aka vorian) for preparing these packages.

If you want to see your name above, then join the Kubuntu Team.
More information is available in the Kubuntu Wiki