I just wanna share how I easily upgraded a magento website from version 1.9.1.1 to 1.9.2.4.

Before you do the upgrade, make sure to create a backup file of your magento website, including the files and database.

Tip: The database file will surely be very big, which will take much time if you download it to your desktop. I suggest that you just create a copy of the current database on the server. To do so, go to phymyadmin, then click on the magento database. Click on Operations. Look for the Copy database field to and enter a name for your backup database. Refer on the image below:

Upgrading Magento

1. Copy all the files of version 1.9.2.4 on the root of your magento website. This means that some files will be overwritten.
2. Login to the admin section, then go to System -> Cache. Check all the items and select refresh from the drop down. Click OK.

Check the website and make sure that everything looks fine.