☑ [Mailing List mode] Replies should start with a Re:

[downey (Michael Downey)]

As far as I understand your request, you can already configure this in the site settings by using the %{optional_re} in your subject format:

Customize subject format for standard emails

So you want to customize subject format for standard emails? Great, let’s get started! The subject for standard emails can be customized from: Admin / Settings / Email / email subject [image] Available formatting options are: %{optional_re}[%{site_name}] %{optional_pm}%{optional_cat}%{topic_title} %{optional_re} → Re: (applicable if the post is a Reply) %{site_name} → Community Title %{optional_pm} → [PM] (applicable if the post is a Personal Message) %{optional_cat} → [category…