Tails includes an automatic mechanism to upgrade a USB stick to the latest version of Tails. When an automatic upgrade is performed, only an *upgrade package* is downloaded. The upgrade package contains all the changes made to Tails since Tails was first installed or was last manually upgraded.
To check which version of Tails you are currently running, choose <span class="menuchoice"> <span class="guimenu">Applications</span> ▸ <span class="guisubmenu">Tails</span> ▸ <span class="guimenuitem">About Tails</span></span>.