This is a guide how to upgrade Joomla to a newer version. Why should you upgrade? First and foremost, because you want your Joomla website to be secure. All dynamic websites are more or less vulnerable to attacks by hackers, who might want to add spam to your website, damage it, or get inside to steal user information. The Joomla developers are determined to be one step ahead the hackers at all times, but in order for you to benefit from their efforts to keep Joomla safe, you need to keep your Joomla installation up to date. So make sure you check now and then for new Joomla versions, and upgrade your Joomla whenever there is a new version available that is said to deal with security vulnerabilities.

Here is how to upgrade your Joomla to a newer version:

• Important: Backup your website’s files and database. 
• Find out what Joomla version you have today:
  • On Joomla 1.5 sites, the version number is shown in the upper right corner of your Joomla administration panel.
  • On Joomla 2.5 sites, the version number is shown in the footer of your Joomla administration panel.
• If you have a Joomla 1.5.x site:
  • Download the appropriate upgrade patch. For example, if you have Joomla version 1.5.7 and you want to upgrade to version 1.5.26, you download the patch named Joomla_1.5.0_to_1.5.26-Stable-Patch_Package.zip. Find the proper Joomla upgrade patch here: Joomla files »
  • Unzip the patch on your local computer.
  • Upload the files via FTP to the web server and let them overwrite the files of your existing Joomla installation.
• If you have Joomla version 2.5.4 or newer:
  • In the back end of your Joomla site, navigate to Components → Joomla Update.
  • Click on Install the Update
  • Wait until the process is completed.
• If you have Joomla version 2.4.3 or older:
  • In the back end of your Joomla site, navigate to Extensions → Extension Manager and open the Update tab.
  • Click on the Purge Cache icon to clear out the cache.
  • Click on the Find Updates icon in the toolbar. If there is an available update, the screen will list it.
  • Select the update (using the checkbox) and click on the Update icon in the toolbar. 
  • Wait until the process is completed.

Caution!

Make sure you backup your Joomla installation before you upgrade. It might happen that some 3rd party plugins or components are not compatible with the newer version of Joomla. Fortunately such problems are rare, but if you have made a backup before you start, you’ll be safe if something would go wrong!