* Updated in December 2015
Joomla! 3.0 was released a long time ago (and now the latest version is Joomla 3.4), so if you want to upgrade your website from Joomla 2.5 to Joomla 3.x, you can follow the steps below. Let's take a look!
Before you decide to upgrade your Joomla website:
1. Back-up your website
To back-up your website, you should use Akeeba back-up. If you do not know how to back-up your website, you can read instructions here: How to use Akeeba to backup your site..
2. Check to make sure all your running extensions are the latest version
In your Joomla back-end, check the "Extension Manager" to make sure that you are running the latest version of each extension.
3. Make sure you are running latest version of Joomla 2.5 (current version is 2.5.14)
Check Joomla version
4. Check your system to make sure that it meets Joomla 3 requirements
In your Joomla back-end, Go to "Site" -> "System Information", check all your settings and make sure that they meet all the requirements here: http://www.joomla.org/technical-requirements.html.
Check all settings
Joomla 3.x requirement:
Joomla 3x requirements
5. Check all extensions / templates for Joomla 3.x compatibility
You need to check all the templates and extensions that you want to use on your website to make sure that they are now compatible with Joomla 3.x. Some Joomla extensions do not support Joomla 3.x
6. Create a test site
If your website meets all the requirements above, you should create another back-up site and a test site on your server in a sub-folder. If you don't know how to create a test site, you can read a tutorial from Ostraining here.
7. Try upgrading in the test site first
Choose short term support
Finish upgrade process
8. Apply the upgrade in the live site
After you successfully upgrade Joomla on your test site, you do the same process in your live site.
I have just instructed you how to upgrade your Joomla website from Joomla 2.5 to Joomla 3.x, and I hope that this blog post is useful for you.
Moreover, if you want us to write about any Joomla topic, just feel free to contact us and we will consider writing about it. As usual, any comments are welcome!