We are often asked the question when we will officially stop supporting Joomla 1.0.x and, given the huge install-base, it's not an easy question to answer. We know that the code originates from several years ago and is certainly showing its age (Mambo 4.5.2 was released in early 2005, but the codebase originates partly from 4.5, released in December 2003). To recap our short history, the Joomla Project originated from a fork of the Mambo Project on August 17, 2005. Shortly thereafter, Joomla 1.0 was released on September 16, 2005 and was an improved version of Mambo 4.5.3 (you can still find that code in subversion). The announcement of the Alpha version of Joomla 1.1 was made on October 27, 2005 and this version was later on renamed Joomla 1.5. What began as a minor update turned out to be a full re-write of the codebase and the current version of Joomla was released on January 22, 2008.
Since then, seven versions of Joomla 1.5 have been released. Download numbers and usage have increased exponentially, evidenced by nearly 7 million downloads. In January 2008, just 15% of newly posted extensions were Joomla 1.5 native and that percentage has recently soared to 73%. The adoption rate of Joomla 1.5, by both users and developers alike, has occured at an amazing rate and demonstrates an untold level of commitment to the Joomla Project on both sides.
But now it's time to say our farewells to our old friend Joomla 1.0. As of July 22, 2009, the Joomla 1.0.x series will no longer be supported. As a user, is it required that you upgrade from Joomla 1.0.x? Absolutely not since security upgrades will be supported until this date. But if you're a user who hasn't yet upgraded to Joomla 1.5, you should do so in order to start reaping the benefits the latest version has to offer. If you're a developer in that small minority who hasn't yet become Joomla 1.5 native, this is your last call to join the majority of developers who have already discovered the power and ease of the Joomla 1.5 series.
In the meantime, we are working diligently on Joomla 1.6 (with its new ACL), which promises to be the most exciting release for Joomla yet.