Unlike with the OS Kernel (the part that deals with your Hardware) there are however certain type of applications that we use quite frequently and we have to rely on the latest updates from the developers since they'll help us to enhance the security + may add some speed in general, which are always more than well come :D.
The web browser is the best example, especially concerning nowadays ;-). Google Chrome web browser has a very short time-line between versions which is working quite nicely for them at the moment which was shortly followed by Mozilla foundation with their famous highly secure web browser the Firefox. Now as a result unlike in the past, we as users can have new versions (updates and interesting features) in a much more faster "cycle", which is a good thing, right?.
In that sense if you arrogantly refuse to give up the old Ubuntu version which works quite nicely for you :P but still would like to install the latest Firefox 5 which comes with few new features but less GUI changes such as ...
*. Over 1000 of bug-fixes.
*. Better HTML5 support (the new era of Internet :)).
*. CSS animations.
*. Do Not Track - A Web standard which web browser developers "sign-in" to let the users know that their web browser is highly secure concerning users privacy thus no data will be "gathered" without their approval.
*. Better web page loading (layout detection) support for the mobile version ... are just a few to mention.
In that case, you can install Firefox 5 in Ubuntu 10.10 Maverick Meerkat and 10.04 Lucid Lynx by using the Mozilla's official PPA channel. To do that, as usual, open your GNU/Linux Terminal and enter the below command.
sudo add-apt-repository ppa:mozillateam/firefox-stableYep... that should do it. Enjoy!.
sudo apt-get update
sudo apt-get upgrade