Updating to Joomla 2.5
NOTE: Do not do this on a live server, backup and test mileage before deploy as components and modules might not be available. Also templates need to be updated
It’s getting pretty easy to update things these days and Joomla is no exception. There is a component that you can get for the joomla 1.5 branch and later that is called jupdate. This component works pretty good as long as your permissions are set correctly. IE if you are not running as a specific user in php that has write permissions to the root of your site, then it may be a problem during the update phase.
As allways before you update make sure you take a backup. There are good tools such as Akeeba backup that help automate the process, but I would also recommend that if you have Joomla 1.5 branch that you update to the latest first. The procedure for doing that is usually pretty simple as joomla provides differential updates for every version save post 1.5.23 versions. This means that you usually have to update to 1.5.23 and incrementally after that to 1.5.24 to 1.5.25, and I don’t believe there is a 26 out there yet.
Once you have updated latest 1.5 you can take a proper akeeba backup with the latest version of that component. Then you can deploy your j2.5 upgrade process.
After the j2.5 update, you should have the regular site, and a new subfolder that you can view the updated site in and tweak things such as components/plugins/modules/templates until you are ready to deploy live.