Starting with Fedora 13, installing an Alpha or Beta milestone puts you on the Branched release path. You shouldn't need to do anything to get the final public release, other than install package updates as they become available. You can use "yum update" or wait for desktop notification. There may be some differences from a fresh install because the installer can do certain things slightly differently than the package update system.
If you have installed Rawhide, you would actually need to downgrade to get the final release, which is not recommended. (It might be easier to wipe the system and install from scratch.)
Alternatively, you can switch to the Branched pre-Alpha release immediately after it becomes available. See Releases/Branched#Yum_update_from_previous_official_release for how to do this using yum.
After updating to final, I see the new fedora and updates repos, but why is my rawhide repo also still enabled?
This will happen if you have manually modified your /etc/yum.repos.d/fedora-rawhide.repo file before updating 
fedora-releasemirrorlist= to baseurl= for a repository definition, this situation occurs. Once fedora-rawhide.repo.rpmnew. To disable Rawhide, either toggle enabled=0 in your modified configuration, select the Software Sources application from System > Administration > Software Sources on the menu, or run this command:
su -c 'mv /etc/yum.repos.d/fedora-rawhide.repo.rpmnew /etc/yum.repos.d/fedora-rawhide.repo'
I found a Fedora 40 ISO leak before release day! Is it legit or is it exploited?
The only way to know for sure is to verify the leaked SHA256SUM CHECKSUM file's GPG signature (if available) with the official Fedora GPG key. If you can't, or won't do this, it's safer to just be patient and wait for release day. Also note that even if the early leak does check out, it might not be the FINAL release. Fedora has in the past had to re-push last-minute changes to the official releases.
If I report my problem to fedora-test list or post in fedora forum, will my issues reach the developers?
You can use such avenues for discussions however for maximum efficiency, we always recommend that all actual bugs be reported to the Fedora bug tracker (Bugzilla) against the appropriate package in rawhide. This is the only assured way of reaching the right developers.
When is Fedora 40 going to be released?
An up-to-date release schedule is always maintained at Releases/40/Schedule.
What are the new features in Fedora 40?
The Fedora_12_Announcement and Fedora 40 feature list has more details.
Should I upgrade to Fedora 40?
We offer you the choice of the greatest and latest release. Per the Fedora lifecyle policy, each release of Fedora is maintained until a month after the second following release. For example, Fedora 38 will stop getting updates a month after Fedora 40 release. We highly recommend that users of unmaintained, "end-of-life" (EOL) releases upgrade to a newer release to continue getting critical security fixes.
How can I upgrade?
Refer to Upgrading.
Where can I get support for 40 pre-releases?
For IRC Support, please use the #fedora-qa channel instead of the main #fedora channel. The FedoraForum site has a dedicated forum for Alpha and Beta pre-releases; please use that forum instead of the main forum. For email list discussions, please use the fedora-test-list.