I installed Fc24 beta a month ago on a new laptop
Ive tried upgrading to 24-final, unsure Ive succeeded.

https://fedoraproject.org/wiki/DNF_system_upgrade

heres what I get now:

$ sudo dnf system-upgrade download --refresh --releasever 24  --allowerasing --best
Error: Need a --releasever greater than the current system version.

that error suggests upgrade completed.  
BUT

$ sudo dnf system-upgrade reboot
Error: system is not ready for upgrade

that could be either because it isnt ready (for an unobvious reason)
or because its already complete, and not ready for F25 yet 

Im pretty sure I ran this or similar shortly after final,
but I also ran it on several other boxes,
without keeping notes,
so not sure of current state (on any of them :-(

-d 7  seems to say Ive succeeded....

]$ sudo dnf system-upgrade download --refresh --releasever 24  --allowerasing --best -d 7 
timer: config: 3 ms
cachedir: /var/cache/dnf
Loaded plugins: generate_completion_cache, download, copr, reposync, protected_packages, system-upgrade, noroot, config-manager, playground, Query, needs-restarting, debuginfo-install, builddep, langpacks
langpacks: No languages are enabled
Error reading file : /var/lib/dnf/plugins/langpacks/installed_langpacks as it does not exist
initialized Langpacks plugin
DNF version: 1.1.9
Command: dnf system-upgrade download --refresh --releasever 24 --allowerasing --best -d 7 
Installroot: /
Releasever: 24
Base command: system-upgrade
Extra commands: ['download']
Cleaning up.
Error: Need a --releasever greater than the current system version.


If youve succeeded in your install,
what happens if you do this ??

dnf system-upgrade reboot -d 7