So for all the fans out there of Ubuntu who are currently using or want to use Ubuntu, here are some tips. Direct upgrade to Ubuntu 10.04 is only available for Ubuntu 8.04 LTS, Hardy Heron, and Ubuntu 9.10 versions. It's quite heart breaking but not to worry people using other versions can also upgrade to Ubuntu 10.04 but the process is a bit lengthy firstly you have to upgrade to the supported versions. I know Ubuntu lovers won't mind it. It's recommended that before you upgrade to Ubuntu 10.04 you must go through Ubuntu release notes.
Ubuntu 9.10 to Ubuntu 10.04 LTS Upgrade through Internet
What's recommended is the network update or upgrade through Internet. The most important step is to take the back up of the files before you start upgrading to the latest version. Oops did you miss to take the back up don't worry, if every thing goes well you won't miss on to the files, but even if you loose some files you can go for third party Linux data recovery software.
After the data protection lets start with Upgrade process.
1) Click on to the System tab>>Administration>>Upgrade
2) You will find a “Check “ button, click the check button to check new updates.
3) If you find any updates please install those update by clicking on to “Install Updates” button.
4) Then press “Check” again once the upgrade is complete.
5) A message will appear stating new release is available.
6) Click the “Upgrade” button.
7) Last step is to follow the instructions on the screen and hit “Upgrade”. Ubuntu 10.04 is ready to use once you reboot your system.
Now, for Ubuntu 8.04 and Hardy Heron users steps to upgrade to Ubuntu 10.04
The first step remains same please back up your data if you don't want to use any Linux recovery software.
Network upgrade or the Internet Upgrade is recommended here too.
1)Press Alt+ f2
2)Type update-manager--devel-release
3)Hit the check button to check if any new update is available
4)If new updates found install them through “Install Updates” button.
5)Check for the updates again.
6)A message will appear informing you about the availability of the new release.
7)Click “Upgrade” and follow the instructions.
If you want to know about the versions supported by the Ubuntu 10.04 you can refer to Upgrade Notes.
This might prove helpful if you are upgrading to the new release.