Suppose you are still using joomla 1.0.x and you are rewriting your URL's to www.yoursite.com/content/view/[article_id]/[section_id]. You want to migrate to joomla 1.5.x but you don't want to lose your url's.

After upgrading to joomla 1.5 you can get back your joomla 1.0.x url's by putting the following lines in your .htaccess file:

RewriteRule ^content/view/([0-9]+)/([0-9]+)$ index.php?option=com_content&view=article&id=$1&Itemid=$2
RewriteRule ^content/view/([0-9]+)/([0-9]+)/$ index.php?option=com_content&view=article&id=$1&Itemid=$2

Add these lines after the line "RewriteEngine On" but before the Joomla Core SEF section in your .htaccess file.