I run this command on my f23:

> sudo dnf system-upgrade download --releasever=24 --allowerasing -y

After 3,2 Gb of download I have get this error:

> ...
>  freetype                       i686   2.6.3-2.fc24               fedora  366 k
>  freetype                       x86_64 2.6.3-2.fc24               fedora  360 k
>  freetype-devel                 x86_64 2.6.3-2.fc24               fedora  447 k
>  freetype-freeworld             x86_64 2.5.5-2.fc24               rpmfusion-free-updates-testing
> ...
> The downloaded packages were saved in cache until the next successful transaction.
> You can remove cached packages by executing 'dnf clean packages'.
> Error: Package freetype-freeworld-2.5.5-2.fc24.x86_64.rpm is not signed

Some suggest?

--
Dario Lesca
(inviato dal mio Linux Fedora 23 Workstation)