A new version of Ubuntu is released every 6 months; the Update Manager should inform you when a new version is available for download. To check for a new version:
1. Open Software Sources (System ▸ Administration ▸ Software Sources) and select the Updates tab.
2. Under Release upgrade, make sure that Normal releases is selected and click Close.
3. Open the Update Manager (System ▸ Administration ▸ Update Manager), click Check and enter your password if prompted. Wait for the list of available updates to be downloaded.
4. If a new version of Ubuntu is available, a box at the top of the window will appear saying that a new distribution release is available.
5. To upgrade to the latest release, save all of your open documents and click the Upgrade button in the Update Manager.
Upgrades usually take a while to complete. Typically, around 700MB of packages must be downloaded and installed, although the actual figure will depend on how many packages are already installed on your computer.
You can only upgrade to the latest Ubuntu release if you are running the second most recent release. If you have an older release, you must upgrade to the next release after that, and so on until you are running the most recent version. For example, users of version 7.10 would first have to upgrade to version 8.04 before upgrading to version 8.10. An exception to this rule is with LTS (Long Term Support) releases. You can upgrade directly from the previous LTS release to the current release.