Where is the auto update for Joomla?
From Joomla! Documentation
Starting with version 2.5.4, the auto update for Joomla is now located in Components→Joomla! Update, as shown here:
Extensions are still updated using the Extension Manager (Extensions→Extension Manager). If you click on the Joomla! Update icon in the Control Panel, it will link you to the Joomla! Update component automatically.