Im trying to use a third party email relay to send my emails with the newsletter module. I have the function all set and ready but when I try to swap out the mail() function in my Email.php file it seems to be sending the same way it has always used. Does the newsletter module not use the Email class? If not what does it use and where can i find it? Im still pretty new with SilverStripe.
I'm pretty sure newsletter does use the email class (https://github.com/silverstripe-labs/silverstripe-newsletter/blob/master/code/email/NewsletterEmail.php) perhaps multiple mail() calls you may have missed. Editing the core mail class is probably not wise as it'll make upgrading hard. You can provide your own Mailer to handle sending email through something other than mail(). See PostmarkMailer as an example that goes over postmark (https://github.com/fullscreeninteractive/silverstripe-postmarkmailer)