Package: thunderbird Version: 1:60.0-3~deb9u1 Severity: serious thunderbird: Breaks: enigmail (< 2:2~) but 2:1.9.9-1~deb9u1 is installed Breaks: xul-ext-sogo-connector (< 31.0.5-2~) but 31.0.3-3 is installed
thunderbird >= 1:60 should be at stretch-backports instead of stretch repository, and there will be possible to introduce higher enigmail and gnupg versions. This is related to bug report: https://bugs.debian.org/909000