Joomla 1.5 Legacy

In early 2008, the Joomla team released Joomla 1.5.  To learn more about this release, read our article about Joomla 1.5 Native.  The Legacy plugin is a system plugin created by the development core team to allow for a smoother transition for developers and sites to move from Joomla 1.0 to Joomla 1.5 by re-implementing many of the functions that were removed from the Joomla 1.5 release.

Legacy Performance Concerns

There are many topics concerning the performance of a system with the legacy plugin enabled.  The general consensus is that it adds a <5% performance penalty to any site, and in most cases, it's much much less.  The plugin itself is written to simply define many of the 'old' functions and use the new Joomla 1.5 framework to implement them.  So, while the plugin code is rather large, on any given site, for any given Legacy component, very little additional code is called for each page rendered.

Significance of the "Joomla 1.5 Legacy" Extension Attribute

A component marked as Joomla 1.5 Legacy requires the Legacy system plugin to be enabled to function.  Either the extension was written only for Joomla 1.0, or it's still in a development transition period and has partially implemented the new Joomla 1.5 development model.