Firefox 71.0 release information; last Firefox release of 2019. New versions to be released later today for all Firefox channels. Firefox Beta and Dev are upgraded to version 72, Firefox Nightly to version 73, and Firefox ESR (Extended Support Release) to version 68.3 https://www.ghacks.net/2019/12/03/firefox-71-0-release-information-last-firefox-release-of-2019/ Releasenotes not yet updated https://www.mozilla.org/en-US/firefox/71.0/releasenotes/
Some Windows users who had previously installed and uninstalled Comodo antivirus software may not be able to start Firefox. Information on how to resolve this issue is described on support.mozilla.org or in the support knowledgebase.
The Techdows article Fix Firefox 71 Does Not Start After Update and Firefox Forum Moderator philipp’s post at https://support.mozilla.org/en-US/questions/1274248#answer-1270830 both note that the FF 71 startup failure can be caused by a Comodo file named IseGuard64.dll or IseGuard32.dll (or something similar) that is normally located C:\Windows\system32\. According to the Techdow article this problem .DLL file may be present with currently running or previously uninstalled Comodo products.