Per https://glandium.github.io/firefox-linux-compat-matrix/#scope=build&version=115&show_eol=false this leaves out Ubuntu 16.04, which hasn't built a newer version of Firefox since version 88.0, and SUSE SLE-12-SP4, which goes EOL next month, so before 115 is released. Differential Revision: https://phabricator.services.mozilla.com/D178485