The Drupal and Joomla projects are both open source collaborations which release periodic updates to the codebase. You should always keep the code updated to the latest stable version that has been released since they often include security updates in addition to new features or bug fixes. (Keep in mind that you should be tracking and updating both the core code as well as any contributed extensions/modules that you may be using.)

Luckily, this process is usually fairly straightforward. The most common type of release includes security updates and bug fixes and involves simply copying new files over top of the current files on your web server using FTP software such as Cyberduck (Mac) or Filezilla (PC). Less common are the major releases that also add new features and they occasionally have more in-depth processes for updating, which are documented in a text file packaged with the update.

Joomla update manager
Drupal update notifier

Updating Joomla core

We highly recommend Sam Moffatt's Update Manager for managing the core updates on your Joomla installation. It provides a simple browser-based option in your administrator panel which will guide you in downloading, extracting and applying the latest Joomla core update. Sam also indicates that in the future extension developers will be able to tie into this system so that you can manage updates to your contributed extensions in the same way. This allows your team to manage core updates even if you aren't confident using FTP or similar methods to transfer files.

Updating Drupal core

Drupal comes with a module called "Update status" enabled by default. This module checks whether there are updates to either the core Drupal files or any contributed modules you have installed. If so, it will display a notification on the page for administrators. You can click to see which updates are available and then download the updated files directly. You have to unpack and transfer the files to the appropriate directory (such as /sites/all/modules/) using FTP. It's important to also run the update.php script after you update modules so that any database modifications can be applied, located at http://www.yoursite.org/update.php.

Conclusion

It's critical to the security of your site to keep your files updated. You can use the methods described above with varying levels of technical experience, or we also offer support packages to groups that have partnered with us for their non-profit web design needs and can offer to help you keep your site updated if you need a hand from outside your organization. Just give us a shout and we can help work out the details.