https://help.ubuntu.com/community/UpgradeNotes#From_10.04_LTS_to_10.10

https://help.ubuntu.com/community/MaverickUpgrades 

Network Upgrade for Ubuntu Desktops (Recommended)

You can easily upgrade over the network with the following procedure.

1. Open the Software Sources application from the System -> Administration menu

2. Select the sub menu Updates from the Software Sources application
3. Change the Release Upgrade drop down to "Normal Releases" and close the application

4. Press Alt-F2 and type update-manager

5. Click the Check button to check for new updates.

6. If there are any updates to install, use the Install Updates button to install them, and press Check again after that is complete.

7. A message will appear informing you of the availability of the new release.

8. Click Upgrade.

9. Follow the on-screen instructions.

Network Upgrade for Kubuntu Desktops (Recommended)

Direct upgrades to Kubuntu 10.10 are supported from Kubuntu 10.04 LTS only.

Upgrade Kubuntu 10.04 LTS to 10.10

Network Upgrade for Ubuntu Servers (Recommended)

1. Install update-manager-core if it is not already installed:

   sudo apt-get install update-manager-core

2. edit /etc/update-manager/release-upgrades and set Prompt=normal

3. Launch the upgrade tool:

   sudo do-release-upgrade

4. Follow the on-screen instructions.

Network Upgrade for Ubuntu Desktops (Recommended)

You can easily upgrade over the network with the following procedure.

1. Open the Update Manager application from the System → Administration menu.

2. In Update Manager, click the Settings... button, and enter your password to start the Software Sources application.

3. Select the sub menu Updates from the Software Sources application.

4. Check the "Release upgrade - Show new distribution releases" drop down to make sure "Normal releases" is selected, and change it if otherwise.

5. Close the Software Sources application and return to Update Manager.

6. In Update Manager, click the Check button to check for new updates.

7. If there are any updates to install, use the Install Updates button to install them, and press Check again after that is complete.

8. A message will appear informing you of the availability of the new release.

9. Click Upgrade.

10. Follow the on-screen instructions.

Network Upgrade for Kubuntu Desktops (Recommended)

Direct upgrades to Kubuntu 11.04 are supported from Kubuntu 10.10 only.

Upgrade Kubuntu 10.10 to 11.04

Network Upgrade for Ubuntu Servers (Recommended)

1. Install update-manager-core if it is not already installed:

   sudo apt-get install update-manager-core

2. edit /etc/update-manager/release-upgrades and set Prompt=normal

3. Launch the upgrade tool:

   sudo do-release-upgrade

4. Follow the on-screen instructions.

Before You Start

• You can directly upgrade to Ubuntu 11.10 ("Oneiric Ocelot") from Ubuntu 11.04 ("Natty Narwhal") only.
• Be sure that you have all updates applied to your current version of Ubuntu before you upgrade.

• Before upgrading it is recommended that you read the release notes for Ubuntu 11.10, which document caveats and workarounds for known issues in this version.

If you have a version of Ubuntu other than 11.04, please see UpgradeNotes for information on how to upgrade.

Upgrade from 11.04 to 11.10

Network Upgrade for Ubuntu Desktops (Recommended)

You can easily upgrade over the network with the following procedure.

1. Open the Update Manager application from the System → Administration menu.

2. In Update Manager, click the Settings... button, and enter your password to start the Software Sources application.

3. Select the sub menu Updates from the Software Sources application.

4. Check the "Release upgrade - Show new distribution releases" drop down to make sure "Normal releases" is selected, and change it if otherwise.

5. Close the Software Sources application and return to Update Manager.

6. In Update Manager, click the Check button to check for new updates.

7. If there are any updates to install, use the Install Updates button to install them, and press Check again after that is complete.

8. A message will appear informing you of the availability of the new release.

9. Click Upgrade.

10. Follow the on-screen instructions.

Network Upgrade for Kubuntu Desktops (Recommended)

Direct upgrades to Kubuntu 11.10 are supported from Kubuntu 11.04 only.

Upgrade Kubuntu 11.04 to 11.10

Network Upgrade for Ubuntu Servers (Recommended)

1. Install update-manager-core if it is not already installed:

   sudo apt-get install update-manager-core

2. edit /etc/update-manager/release-upgrades and set Prompt=normal

3. Launch the upgrade tool:

   sudo do-release-upgrade

4. Follow the on-screen instructions.