In msmtp 1.8.2 and mpop 1.4.3, when tls_trust_file has its default configuration, certificate-verification results are not properly checked.
https://marlam.de/mpop/news/mpop-1-4-3/
https://gitlab.marlam.de/marlam/mpop/commit/b51a6c6b8b83bf0913cc52fa2ff64307e987a5b8