Potential backward compatibility issues in Joomla 1.7 and Joomla Platform 11.2

From Joomla! Documentation

This documents track potential backward compatibility issues for Joomla 1.7 and Joomla Platform 11.1 which will be included in Joomla 1.7. Listed are issues which potentially breaks extensions and newly deprecated APIs.

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Platform Joomla 11.1[edit]

  • JPATH_PLATFORM is now used instead of JPATH_LIBRARIES (JPATH_LIBRARIES will continue to be supported for version 1.7)


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]

JError & JException[edit]

JError and JException have been deprecated with Joomla Platform 11.1. Please see Exceptions and Logging in Joomla 1.7 and Joomla Platform 11.1 for more information.[4][5]


  • JLoader can't load files multiple times anymore.[6]


  • 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().[7]


  • JUpdater:: arrayUnique() has been deprecated Use JArrayHelper::arrayUnique() instead. Note that the later is static.[8]


  • MooTools Core has been updated to version 1.3.2, MooTools More to Due to a change in JSON handling a slight change in behavior can occur. More details can be found on the MooTools Wiki.[9]
  • checkAll() has been deprecated, use Joomla.checkAll() instead. Note that Joomla.checkAll() doesn't include some legacy functionality.[10]

CMS Joomla 1.7[edit]

General Coding Principles[edit]

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.


  • TinyMCE has been updated to the 3.4 series requiring new language files and potentially breaking TinyMCE plug-ins.[11]


  • MooTools Core and MooToools more will not always be loaded in the backend as it was in the past. Extensions have to specifically include it.[12]


  • The link to "View Site" is no longer included in mod_status. Administrator templates have to add it themselves.[13]


  • mod_online and mod_status have been removed[14]


  • mod_menu uses a class instead of an id attribute for the itemid.[15]