You could try upgrading to Fedora 25 if that has the version you're
looking for. Clone your Template (so you can go back to the old one if
there are any issues) and follow the instructions here:
https://www.qubes-os.org/doc/template/fedora/upgrade-23-to-24/
and just replace all instances of 23 and 24 with 24 and 25 respectively
and it should work. Qubes does have a repository for Fedora 25 packages
for VMs already, although there may be some issues with some packages
due to Fedora's shift from X to Wayland which is why I think there isn't
an official Fedora 25 template yet.