From this thread https://www.reddit.com/r/firefox/comments/brjj82/firefox_67_thinks_its_an_old_version_and_wont/?ref=readnext
"From looking at the compatibility.ini for the old profile vs the new one it looks like the long version number for the newer Ubuntu is slightly smaller.
18.04 profile: 67.0_20190517140819/20190517140819
19.04 profile: 67.0_20190517140251/20190517140251"
From this thread https:/ /www.reddit. com/r/firefox/ comments/ brjj82/ firefox_ 67_thinks_ its_an_ old_version_ and_wont/ ?ref=readnext
"From looking at the compatibility.ini for the old profile vs the new one it looks like the long version number for the newer Ubuntu is slightly smaller.
18.04 profile: 67.0_2019051714 0819/2019051714 0819
19.04 profile: 67.0_2019051714 0251/2019051714 0251"