I decided at my own risk to update on my Ubuntu desktop to 9.04 beta.
I will say in advance that everything went well! ;-) I offer you a screencast of the whole update process and my comments where they will be needed.
And so let's go!
Open the console and execute:
~$ update-manager -d
The update manager opens with the distribution update button.

Click update. A release notes window will appear.

From it we learn that this is a beta release and it is not recommended to install it on a working system. But we risk ;-)
Next, the update process begins.

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Get new package listings.

Next, the system will warn us about disabling sources of third-party packages.

Now the update system will check for about 2-3 minutes what needs to be updated.

After checking all the necessary system will tell which packages will be removed, updated and which are installed.

The loading of packages starts ... It took me about an hour's pool for which ~ 900MB of new packages were downloaded.

Once all the packages have been downloaded, the installation phase begins.

You can open the terminal for a more lively process.

At this stage, my network disconnected and rose again only after the end of the update and reboot. There will also be a few questions about the replacement of configuration files (all answered to replace).
As soon as everything is set, the system cleaning is started.

After checking the installed packages, Ubuntu will offer to remove older and more unnecessary packages.

We agree with her in order not to produce debris on the screw.
After this, the system update can be considered complete.

Click on the reset button and enjoy the new system!
~$ sudo lsb_release -a
[sudo] password for tux:
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu jaunty (development branch)
Release: 9.04
Codename: jaunty
The first thing that caught my eye after the update is the promised new tooltips and system loading speed (2 times faster).
All now I will test! ;-)
PS: You update the system at your own risk! For all the consequences you are responsible for yourself.zy2: Crosspost from my blog
http://webiteam.ru