can you provide reasoning why this is always okay? I have found some mixed results when looking this up - i.e. I saw that servers should normally never not provide HELO but the reason was that clients might be incompatible - so I don't quite know if that makes this required.
Thank you :)

According to RFC 2821 old servers may support HELO and reply promptly on that (with HELO):

Older client SMTP systems MAY, as discussed above, use HELO (as specified in RFC 821) instead of EHLO, and servers MUST support the HELO command and reply properly to it. In any event, a client MUST issue HELO or EHLO before starting a mail transaction.

So we have few options:

1. Drop such servers (I’m not sure it’s ok)
2. Try such servers as in commit above but to not fail. Maybe we need better policy - try EHLO and then only if server does not know it issue HELO
3. Provide an ability for the user to define that the server is old and we should try HELO.

I find the option 2 the most appropriate. However change of the logic to issue EHLO first looks like a sane improvement

try EHLO and then only if server does not know it issue HELO

do you want to implement that? otherwise I think this is fine and I'll merge as is.

No, not sure that I’ll do it soon. I think it’s fine to merge, as it improves the status quo!

Thank you.