Guide to Upgrading Joomla 1.5 to Joomla 2.5

By Justin Kerr
August 10, 2012

Table of Contents

Are you still running a Joomla 1.5 Web site?  The time to upgrade is now!  Joomla 1.5 goes into retirement as of September 2012, leaving your site without software updates, bug fixes, security patches and community support. Although the upgrade process may seem daunting, this guide provides all the information you need to confidently plan and execute a Joomla 1.5-to-2.5 Web site upgrade.

This article results from a series of presentations about upgrading Joomla delivered in 2012 at the CMSExpo, Joomla Day Chicago, and Joomla Chicago meetings.

If you have a Joomla 1.5 Web site that needs to be updated to Joomla 2.5, the process can seem daunting. Unlike incremental updates (such as moving from Joomla 1.5.25 to 1.5.26), there is no uploadable patch or one-click interface that automatically updates Joomla while retaining all of your site's data, structure, design and functionality. For a variety of reasons, upgrading from Joomla 1.5 to Joomla 2.5 requires more technical knowledge and labor than a simple update to the software.

Joomla Release History

Joomla 2.5 is the latest "long-term release" version of the content management system and the first update of a release cycle pattern that designates the "dot zero" version of the software (e.g. Joomla 3.0) as a cutting-edge version, with the "dot five" version (e.g. Joomla 2.5, Joomla 3.5) serving as long-term releases that promise years of support.  Joomla 1.5 has been an aging version of the CMS for many years; Joomla 1.6, released in January 2011, began the latest update cycle with a fundamental overhauling of Joomla's core code.  Joomla 1.7 followed in the summer, and the decision was then made to change the numbering and release cycle and method. Joomla 2.5 came out in January 2012 and will be supported well into 2014.

On a code level, Joomla 2.5 contains many fundamental differences from Joomla 1.5.  This has proved a special challenge for third-party extension providers, who have had to overhaul the code of their products in order to work on the Joomla 1.6/1.7/2.5 branch.  In some cases, the extension providers have also changed the nature of their products, so the Joomla 2.5-compatible version is significantly different from the Joomla 1.5-compatible version.  In other cases, the extension providers have not provided a 2.5-compatible version at all. Many Joomla 1.5 sites rely heavily on third-party extensions for structuring and displaying content, which adds another level of complexity and labor when moving to Joomla 2.5.

An Upgrade or a "Migration"?

You have to hand it to software developers: They sure can suck at semantics. Upon perusing the official Joomla documentation for upgrading, as well as Joomla communication channels, one will find the upgrade process repeatedly described as a "migration."  Although this may have been a good way to relate how Joomla's code has changed (and the re-coding work required for third-party extension developers), it's a poor way to present the process to the layperson.  Joomla 2.5 is still "Joomla" and has more in common with Joomla 1.5 than differences: They both have Articles, Templates, Plugins, Users and Component and Menu systems.  The core set of Components is nearly the same, and the default administration interfaces are very similar.  Both versions are used and deployed in the same ways, and on the same types of hosting platforms.

The problem with the term "migration" is that it may imply other changes in the mind of a layperson (such as a client).  Is this a migration to a different Web hosting environment?  Are we migrating our Web site to different content management system software?  Despite the not-insignificant work involved in moving to Joomla 2.5 from Joomla 1.5, an "upgrade" remains the best way to describe this type of project.

No Official Solution

Joomla itself has not provided a migration script or process for the Joomla 1.5-to-Joomla 2.5 upgrade.  (However, it's worthwhile to note that Joomla 2.5 and succeeding versions have one-click upgrades integrated as part of the system's core functionality.)  Fortunately, third party developers have come to the rescue!  This guide will examine two of the primary third-party solutions for migrating Joomla's core data, explore the processes involved with handling upgrades of third-party extensions and provide some tips and tricks for managing an upgrade project.