iPhone Reply to All
TL;DR - Listname and Listname-ML are the same
Emails sent to your Listname or Listname-ML address will both go to your mailing list.
The Reply All command on an iPhone works differently than any other email reader
The iPhone / iPad does not enable the Reply All option when the From and To lines in an email are the same address.
If the author of the message has DMARC turned on, then the mailing list address is in the From line, instead of the author.
In addition, there is a Mail-List.com option that always puts the mailing list address is in the From line.
If either of these 2 conditions are met, then we use -ML in the To header.
To compensate, we make the To header be a slightly different email address
We add the -ML suffix to your list name, and then when the email comes to us, we treat it the same as without the suffix.