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.
After starting Tails and connecting to Tor, <span class="application">Tails Upgrader</span> automatically checks if upgrades are available and then proposes you to upgrade your USB stick. The upgrades are checked for and downloaded through Tor.
The automatic upgrade is impossible for technical reasons (not enough memory, not enough free space on the USB stick, and so on). For example, if you get the following error message:
You want to upgrade by cloning from another Tails USB stick which is already up-to-date, for example, when working offline or with a slow Internet connection.
After connecting to Tor, a dialog informs you if you have to upgrade your USB stick using <span class="application">Tails Cloner</span> to a newer version of Tails.
