I finally upgraded to Fedora 30 today, and when I launched Firefox for the first time, it complained that I was running an older version than the last time I’d used it, and needed to create a new profile.
Using an older version of Firefox can corrupt bookmarks and browsing history already saved to an existing Firefox profile. To protect your information, create a new profile for this installation of Firefox.
OK, Firefox did release two emergency updates yesterday. Maybe Fedora 29 got 67.0.4 and Fedora 30 got 67.0.3, and DNF decided it was important to downgrade to the Fedora 30-provided version?
No, both were still on 67.0.3. So what could be going on?
A quick search turmed up a Reddit thread on the problem that pointed me to the solution: Look for the compatibility.ini file in my Firefox profile, and delete the LastVersion line.
It worked! Firefox launched happily, with all my settings and everything.
I made a note of the version that was in there before, and the version that got placed when I launched it, and that cleared up what had caused the confusion.
Apparently, Fedora built the F30 package earlier in the day than the F29 package! 🤦♂️
Fedora 29: 67.0.3_20190619204842/20190619204842
Fedora 30: 67.0.3_20190619113000/20190619113000
So it was technically “older” … just not in any meaningful sense.