I updated f22 to f23 by running: dnf distro-sync --releasever=23 This made rpmfusion repos unavailable, because they do not exist for $releasever 23 dnf knows that some repos are broken and disables them. dnf distro-sync removes all packages that are not found in repos. Imagine situation when a server with yum repos has an outage. dnf disables the repo(s) and distro-sync removes packages. I'd like dnf not to remove packages by default and introduce an option to allow removing extra packages or re-use --allowerasing. Using -x option to manually exclude packages from distro-sync doesn't help.
Thank you for the report. The distro-sync way of upgrading Fedora is not supported but considering how often repositories are not available, it might be useful in other cases as well. We'll take a look.
*** This bug has been marked as a duplicate of bug 1244175 ***