Backup Your iPhone, iPod or iPad
Before you upgrade your device it’s always a good idea to back up all of your data. This is especially important when you haven’t synced your device in a while. While the chances of a error occurring and forcing you to go full restore are slim, it’s always a good idea to backup your stuff.
Plug your device into iTunes, right click on your device in the left panel. Select Back Up from the drop down menu. It might take a while, but it’s worth it if things going horribly wrong.