Potential backward compatibility issues in Joomla 1.7 and Joomla Platform 11.2

From Joomla! Documentation

Revision as of 02:30, 4 June 2011 by Pasamio (Talk | contribs)


  • JPATH_PLATFORM is now used instead of JPATH_LIBRARIES


JDatabaseQuery is now abstract due of the work done to support new database engines (Windows Azure and Microsoft SQL Server). This means you must use $db->getQuery(true); to instantiate a query as is the correct practice in Joomla 1.6.


  • getHeadData(), setHeadData() and mergeHeadData() are from now on only present in JDocumentHTML. They have been removed from JDocument and JDocumentXML.[1]


  • JDocumentHTML::$_links has changed to a multidimensional array. Also the rendering of the link elements has been moved from JDocumentHTML to JDocumentRenderHead.[2]


  • A div element with the ID "system-message-container" is always rendered, whether there are messages or not. This ID should not be used in any extension or template.[3]


  • JLoader can't load files multiple times anymore.[4]


  • JLog has shifted to joomla.log.log from joomla.error.log and features support for multiple loggers.


  • The unused parameter $akey has been removed from JURI::buildQuery().[5]


General Coding Principles

Within the new Joomla release cycle, developers need to be conscious of more frequent changes to version numbers. If you are doing hard checks against, for example, a version number exactly equal to "1.6" then as we move to 1.7, those checks may fail with unexpected results. You should ensure that version checks appropriately allow for future increments like 1.7, 1.8, 2.0, 3.0, and so on.


  1. Remove getHeadData(), setHeadData() and mergeHeadData() from JDocument since it only applies to JDocumentHTML. (GitHub)
  2. Move the rendering of HTML link elements to JDocumentRendererHead. (GitHub)
  3. Modify JDocumentRendererMessage to always render <div id="system-message-container"></div>. This makes it possible to render messages via JavaScript. (GitHub)
  4. Use include_once instead of include in JLoader (GitHub)
  5. Remove an unused paramet in JURI::buildQuery(). (GitHub)