To upgrade our Magento, we have to follow these steps:

Via content manager
  • Log on to Magento backend
  • Go to System >>Magento Connect >>Magento Connect Manager
  • Fill the credentials
For Magento 1.5 and 1.6 to Magento 1.9.x
  • Under “Install New Extensions”, paste
  • Then install and proceed
For Magento 1.7, 1.8 and 1.9 to Magento 1.9.x
  • Go to Manage Existing Extensions”
  • Click on “Check for Updates”
  • Click dropdown menu behind the extensions
  • Click on Commit changes
  • Magento is updated now
BY Best Interview Question ON 03 Mar 2019