SMTP_SKIP_TLS_VERIFY (and the matching admin setting) turns off certificate
checking for outgoing mail. That escape hatch stays — an install behind an
internal relay with a self-signed certificate depends on it — but until now it
downgraded the connection without a word, and a transport is built per send, so
whoever flipped it had nothing to go on afterwards.
It now warns once per process, naming the host it applies to. Once, not per
mail: a line on every notification is a line nobody reads.
Maurice