1.Backup your data:
Before doing anything Back up any personal data to an external hard drive or to another machine. If there is some unrecoverable error that requires a fresh install, you don’t want to lose any data.
Step 1: Switch to root user.
[geeksite@fedora15~]$ su -
Password:
Step 2: Update Fedora 15 packages.
[root@fedora15~]# yum update
Step 3: Install preupgrade rpm using YUM.
[root@fedora15~]# yum install preupgrade
Step 4: Run Preupgrade.
[root@fedora15~]# preupgrade
Step 5: Click Forward on the Preupgrade window.
Step 6: Select the desired release and click on Apply.
Step 7: Preparing system for upgrade, once packages are downloaded click on Forward.
Step 8: Click on Reboot Now, when you ready to install updates.
Upgrading the packages.
Step 9: Once upgraded machine will restart and you will get the following upgraded grub screen.
Fedora 16 is booting up.
Step 10: Login to fedora 16.
You will get new fedora 16 desktop.
That’s all! Now the machine successfully upgraded Fedora 16 (Verne).