Joomla! 1.5 does not provide an upgrade path from earlier versions. Converting an older site to a Joomla! 1.5 site requires creation of a new empty site using Joomla! 1.5 and then populating the new site with the content from the old site. This migration of content is not a one-to-one process and involves conversions and modifications to the content dump.
There are two ways to perform the migration:
When you Archive an Article, the content is put into a state which removes it from your site as published content. The Article is still available from within the Control Panel and can be retrieved for editing or republishing purposes. Trashed Articles are just one step from being permanently deleted but are still available until you Remove them from the Trash Manager. You should use Archive if you consider an Article important, but not current. Trash should be used when you want to delete the content entirely from your site and from future search results.
To completely remove an Article, select the Articles that you want to delete and move them to the Trash. Next, open the Article Trash in the Content Menu and select the Articles you want to delete. After deleting an Article, it is no longer available as it has been deleted from the database and it is not possible to undo this operation.
The one thing about a Web site, it always changes! Joomla! makes it easy to add Articles, content, images, videos, and more. Site administrators can edit and manage content 'in-context' by clicking the 'Edit' link. Webmasters can also edit content through a graphical Control Panel that gives you complete control over your site.
Joomla! makes it easy to launch a Web site of any kind. Whether you want a brochure site or you are building a large online community, Joomla! allows you to deploy a new site in minutes and add extra functionality as you need it. The hundreds of available Extensions will help to expand your site and allow you to deliver new services that extend your reach into the Internet.