[erlang-questions] SSL 'verify_peer' client option changed between Erlang 19.3/20.1?

[Roger Lipscombe]

I've got some test code where I connect an Erlang ssl client to an
Erlang ssl server on localhost. On Erlang 19.3, it was passing fine.
On Erlang 20.1, it started failing with
{bad_cert,hostname_check_failed}.

Investigation reveals that I'm connecting to "localhost", the server
cert has ".../CN=testserver", and I'm passing {verify, verify_peer} in
the client options.

My question is, basically: why didn't Erlang 19 fail?