Follow up email

[jace]

Email often requires follow-up, if for example the recipient did not respond the first time. Hasmail should facilitate this by allowing the user to:

1. Select a subset of the recipient list, perhaps say everyone who RSVPed with a certain status.
2. Replicate this into a new campaign.
3. Create a new email draft that includes the last draft, with quotes (all lines prefixed with "> " in the plain text version). If a recipient had a custom mail sent to them, that version is quoted for them. Optionally, the user can choose to not quote the previous mail. Risk: if the template was updated after the mail was sent, the recipient will get a quoted version that is different from the original version.
4. Hasmail remembers that this campaign is a follow-up and shows it as such in the sidebar in the Start section (parent-child relationship)
5. Finally, RSVPs will now have to be stored separately from the EmailRecipient model. If a person RSVPs after a follow-up email, it will currently be stored as a response to that campaign, making it harder to see a single RSVP report.

[akshaybhalotia]

This is such an important feature, I came here to open an issue on this and found one that already exists. +100 from me if it helps bumping the priority.

[jace]

We don't have the technical ability to process incoming email at this time. A number of features across projects are waiting for this ability to exist.

[akshaybhalotia]

My use case would be to send a second email to people who haven't responded. This should allow for selecting a subset of recipients and sending email under the same subject, only with fresh text.

[jace]

To send a follow-up and have it thread correctly, we need to preserve the Message-ID header from the original and quote it in the follow-up in References and In-Reply-To headers. (Documentation). We are currently not preserving this header, so it needs to be fixed.