feature: Allow configuring SMTP headers in app-settings

[jesperordrup]

Some SMTP providers need some additional headers when sending. For instance Elastic email https://help.elasticemail.com/en/articles/2376848-how-to-manage-custom-headers

Allow to specify a collection of headers such as "isTransactional" : true when defining smtp server connection would make freescout work with the "pro" smtp servers

https://freescout.umakers.dk/app-settings/emails

[freescout-helpdesk]

Are you sure Elasticemail will read isTransactional header when sending an email via SMTP? All examples in their docs are using REST API and isTransactional is set as parameter when sending a request to REST API. Try to check with them.

[jesperordrup]

Hi freescout

Yep - pretty sure. From the coversation I had with them the other day on their chat:

Also this snip found on https://help.elasticemail.com/en/articles/2376848-how-to-manage-custom-headers

[freescout-helpdesk]

Implemented in the master branch. Add the following to your /.env file and clear cache:

APP_CUSTOM_MAIL_HEADERS="IsTransactional:True"

[jesperordrup]

@freescout-helpdesk wow thats fast :-)

I have to wait trying until your next release.