Thread:Project:Support desk/How to Upgrade MediaWiki 1.12 to 1.24/reply (11)

For your number 1: When you take Postnuke out of the equation, that will make things much easier. In that case I would not only upgrade PHP (which might be slightly more difficult as you would have to compile PHP into your old XAMPP stack). Instead, you can directly start upgrading XAMPP. XAMPP comes with the Apache webserver, with MySQL and with PHP. So if you upgrade XAMPP, these three will automatically be upgraded. That way you can also be sure that all three (Apache, PHP and MySQL) work together properly. When you do that XAMPP upgrade, take care that
 * you do not overwrite or delete the files of your MediaWiki installation (which most likely are in htdocs/) and
 * that you do not overwrite/delete files in the folder mysql/data/ (there are your databases, among them your MediaWiki database).

After the XAMPP upgrade you can then upgrade MediaWiki.