Is there an ENV variable for 'secureConnection' and 'from' for Mailgun?

Is there an ENV variable to set ‘secureConnection’ in Mailgun config ? In the docs, I don’t see a way to pass this variable.

As I manage many Ghost instances for my clients, I’m wondering if I can set secureConnection to true or false when I start Ghost.

Is setting --mailport to 465 or 587 is enough?

Thanks!

config.json

variables from the docs

secureConnection ?
from ?

Same question about from. Can we pass a variable for it?