The post reads:
Those who followed the development trunk have noticed an addition of a new system plugin. Anthony Ferrara has written this plugin and provided me with the details. This plugin Â“SEFÂ” was changed from a content plugin to a system plugin to account for SEF URL issues outside of content.
The change was made because relative links were not resolving properly from modules and templates when SEF URLs were enabled. A system plugin is introduced to take care of these issues. As such, the content plugin Â“SEFÂ” is no longer needed.
The changes to the database simple include changing the sef plugin from Â“content folderÂ” to Â“system folderÂ”, and reordering the system plugins to compensate for the change. The database changes can be made by either placing the migration.php script in the home directory and executing it, or executing the two following queries in MySQL:
UPDATE `jos_plugins` SET `ordering` = `ordering` + 1 WHERE `folder` LIKE Â’systemÂ’;
UPDATE `jos_plugins` SET `name` = Â‘System – SEFÂ’, `folder` = Â’systemÂ’, `ordering` = 1 WHERE element LIKE Â’sefÂ’;
For those who want to upgrade from RC3 to this version (and also the upcoming RC4) need to be aware that this patch needs to be included to make the new code base work with SEF. We currently still have a problem with proper URL generation when the legacy mode is enabled, this problem will be fixed as soon as possible.