Here, We have write article about How to disable admin notification popup in magento.
Every time you log in to the Magento Admin Panel, you see an admin notification popup message telling you there’s a new Magento version. As a developer, it’s best to stay informed about new releases by reading blogs, tweets and lots of other news channels – besides this, upgrades should never be taken lightly. It’s possible to remove this notification popup message.
To remove this notification popup message.
Login to your Magento Admin Panel
Go to System >> Configuration >> Advanced
Disable the Mage_AdminNotification module