Is ARC authentication supported in cPanel?
ARC (or Authenticated Received Chain) is a method to verify email authentication for forwarded messages in an attempt to minimize the failure of forwarded messages when checking DKIM and SPF records. cPanel uses Exim as a message transfer agent (MTA), in which ARC is still considered experimentally supported.
The following feature request has been created on which you can vote and comment if this is a feature you would like to see added to cPanel:
Our feature request site is actively reviewed and curated by our development team to identify potential future build plans and to accept ideas and suggestions from our community. While we cannot guarantee that all requests will be accepted, this is the best way to make suggestions visible to the teams that build cPanel.