Where can i modify the subject of my mails ?

This question is in the top of the support questions.

To have a complete answer, we must classify the mails in three different categories :

1. WordPress mails
2. MailPress mails
3. MailPress newsletters

WordPress mails

The subject of the mails initiated by WordPress (except for multi-site mails & retrieve password mail) is set by code in file wp-includes\pluggable.php.
“WordPress mails” can become “MailPress mails” by checking option in Settings > MailPress > General > Admin > Options > MailPress version of wp_mail (except for multi-site mails).

MailPress mails

formerly WordPress mails (e.g. wp_notify_moderator)

WordPress code is replaced by following code supporting html & plaintext parts.
Theme template ‘moderate’ is required here.

• If the template file do not exist, content and subject (set in code) apply.
• It the template file exists (in parent or child theme),
  • the parent/child template file has no Subject tag in the header, subject set in code applies.
  • the parent/child template file has a Subject tag in the header, template subject applies.

initiated by MailPress (e.g. comments)

For comment notifications, Theme template ‘comments’ is required here.

• If the template file do not exist, content and subject (set in code) apply.
• It the template file exists (in parent or child theme),
  • the parent/child template file has no Subject tag in the header, subject set in code applies.
  • the parent/child template file has a Subject tag in the header, template subject applies.

Newsletters initiated by MailPress

Newsletter definitions are set in xml files (mailpress\mp-content\advanced\newsletters\*.xml).
Theme & subject are set in the <mail> section (e.g. daily.xml).

• the parent/child template file has no Subject tag in the header, subject set in xml file applies.
• the parent/child template file has a Subject tag in the header, template subject applies.

Template without Subject tag in header.
Template with Subject tag in header.