Key Difference: Joomla 1.5 was released on January 22, 2008, while Joomla 2.5 was released on January 24, 2012. Joomla 2.5 brought many upgrades to Joomla 1.5, some of which were already a part of the Joomla 1.6 and 1.7 updates.

Joomla! is a content management framework that allows users to build websites from the ground up without having to learn basic programming language. This CMS is for the people that are not well-versed with anything related to do with designing websites, but wish to do it themselves. It makes it easier for them to establish and maintain websites without having to waste time and money on special designers.

Joomla is free and open-source content management system (CMS) that allows users to build websites and online applications. It is considered to be quite easy to use and understand for many users. Joomla is more commonly used for simple websites, but it can also handle websites that are complex with a little extra training. The company claims that the website can be used for almost any website of any shape and size. Joomla is written in PHP and uses object-oriented programming (OOP) techniques and software design patterns. Joomla offers more out of the box themes and features such as page caching, RSS feeds, printable versions of pages, news flashes, blogs, polls, search, and support for language internationalization. It is currently the second-most used CMS after WordPress. Joomla was created in 2005 following the creation of a website called OpenSourceMatters.org that distributed information to users, developers, web designers and the community in general.

Similar to all software, Joomla has different versions that were added on later with additional features to make the system easier and more user-friendly. Joomla aims at launching a long-term support (LTS) version every 18 months, with small updates available in between. Joomla has stated that each LTS version would end in .5, which means the next Joomla LTS version would be 3.5, followed by 4.5, 5.5, etc. Joomla 1.5 and Joomla 2.5 are two LTS versions of the software. Joomla 1.5 was released on January 22, 2008, while Joomla 2.5 was released on January 24, 2012. Joomla 2.5 brought many upgrades to Joomla 1.5, some of which were already a part of the Joomla 1.6 and 1.7 updates.

Joomla 2.5 came with the following new features and upgrades:

• A new platform: Joomla has changed the base of the CMS, which is now the Joomla Platform Version 11.3.
• Image manipulation with the JImage class and generation of HTML tables with the JGrid class
• A new version of the JavaScript library MooTools is used (1.4)
• Search is reinvented with the new Finder. It has a more Google-like experience. It has more advanced search filters, auto-correct, auto-complete, etc.
• Ability to run Joomla on MySQL and Microsoft SQL Server
• New Offline Mode features (new messages, ability to add images, or offline website during maintenance.)
• User registrations with CAPTCHA
• Mobile enhancements
• Cleaner layouts
• Easier handling for layouts
• Multilanguage capability
• User Notes
• Filtering categories now includes subcategories
• Removed automatic creation of modules for each menu type
• Custom Text Filters are moved to the global configuration
• Administrator can receive a new message when a user creates an account
• Sections are removed, but categories can be nested deeply.
• New access concept
• Multiprocessing
• The system detects available updates and initiates them by clicking on the corresponding button
• New administrator templates and website templates
• New template styles and layouts
• Consistent user interface
• Legacy mode is disabled
• Users can now use unicode in URLs
• Users can allocate meta text and keywords to categories
• Modules can be published time-controlled
• Code Mirror is the new editor, which is supplied in addition to TinyMCE
• New redirect component
• Articles can change the page title and page header separately
• One-click extensions package installer, i.e. components, modules and plugins can all be packaged and installed from a single file

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