To upgrade Fedora in your machine follow the below steps-

1. Take all your important files backup to any external media or hard drive.
2. Verify your current fedora version by executing following commands in terminal

$ cat /etc/fedora-release

If your current version is 22 you will see the following message in your terminal screen Fedora release 22 (Twenty Two)

3. Now firstly upgrade all your existing package for this run the following command in terminal. And after receiving all the updates reboot your machine to apply the changes

   $ sudo dnf update

4. After this you have to install DNF Plugin system Upgrade package by using below command

$ sudo dnf install dnf-plugin-system-upgrade --enablerepo=updates-testing

press Y for yes at the end.

5. Now you have to download the upgrade package for this use below command

$ sudo dnf system-upgrade download --releasever=23 --best

In the above command --best means it will cancel the upgrade and will inform you in case if there are available upgraded packages that cannot be updated due to dependency issues. Along with you can also use --allowerasing option at the end of the command to erase those packages in which there are dependency issues but I would prefer to use command without --allowerasing just to keep the packages as they are. the command will be-

$ sudo dnf system-upgrade download --releasever=23 --allowerasing

Run Fedora Upgrade

6. Before this in previous versions of fedora the upgrade were performed by Fedup updater but now in the newer version it is replaced by dnf. Use below command in your terminal

$ sudo dnf system-upgrade reboot

Your machine will be rebooted and upgrade will start at boot time. It may take some extra time you have to wait until upgrade is not finished, do not turn off your machine or reboot until upgrade is not done.

7. As soon upgrade is finished you machine will reboot automatically and take you to new Fedora 23 with the latest kernel available.