Hello, I'm opening this in reference to merge request #1766 (https://github.com/mantisbt/mantisbt/pull/1766), as requested by dregad.

The first request was to provide some context / rationale for the change. I'm working on a new feature on EmailReporter plugin that requires sending emails with CC and BCC addresses. The intent is to add the ability to notify the email sender when a new issue has been created, notifying at the same tame a static list of email addresses.
ATM the only way to specify CC and BCC fields is by setting the relevant headers via addCustomHeader(), but this implies they will be encoded by PHPMailer.
The pull request adds two optional parameters to email_store() function, containing the CC and BCC arrays of email addresses.

Dregad asked as well if are there additional / modified event hooks required for this. In this case, there aren't.

The last request was to reference this issue's ID in my commit message (i.e. Fixes #xxxx) and then rebase (not merge) my branch on top of latest master.
Once created this issue and obtained the ID I'm going to do this and let you know in a comment when it's done. I will also reopen the merge request on github.

Thank you for your support