As you all are aware of, Magento shows a popup on the new version release if the current magento version is below the latest version.
I want to develop a similar type of popup as soon as user logs in into the admin panel.
The notifications, like "Magento 1.9.1 is now available" come from this RSS feed: http://notifications.magentocommerce.com/community/notifications.rss
It is processed by
Mage_AdminNotification_Model_Feed. Many extensions add their own notification feed by extending this class and overriding
getFeedUrl() and calling
checkUpdate() periodically using a cronjob or on each login using an observer.
Besides that, you can also dynamically add notifications using
addNotice there is also:
for warnings of different severity.