Joomla! is part of the open source community and their source code is freely accessible and can be modified under their license.
Ah, The Love/Hate…
Joomla! support services for those customers currently using Joomla! as their web CMS eXperiencing issues, we lean more towards directing them to WordPress and Drupal if “the juice is not worth the squeeze” to repair their current Joomla! implementation.
In Our Opinion, Joomla Might be Dying!
Between Drupal and WordPress – WordPress being our favorite for most common web sites, most bases are covered with regards to security, longevity, scalability, and features. This means that before even considering the drawbacks of Joomla!, there really is no necessity for it in the market any longer.
Many plugins for Joomla! must be paid for and are no longer supported, potentially due to the low user base. This generally causes the community to not favor the use of such modules, which has also depreciated in the past few years and led to many migrations to either Drupal or WordPress. This results in a smaller Joomla! community, which is infrequently ideal for an open source platform.
Joomla! is also generally less secure than WordPress and Drupal, and the way upgrades are handled from one major release to the next can be very frustrating. Major version releases are really forks to the last version and require more of a migration than an upgrade. Moreover, the site theme and extensions used on the previous version are often incompatible with the new version, which means you have to invest much more time and money when performing what should be a simple upgrade.