Can you use a mailto link to reply to an email and preserve threading?

Question

RFC 6068, section 6.1 has the following example:

An interesting use of 'mailto' URIs occurs when browsing archives of messages. A link can be provided that allows replying to a message and conserving threading information. This is done by adding an In-Reply-To header field containing the Message-ID of the message where the link is added, for example:

<mailto:[email protected]?In-Reply-To=%3C3469A91.D10AF4C@ example.com%3E>

In this example, a mailto link is used to reply to an existing email, using the URL encoded Message-ID. Despite this, I am so far unsuccessful in making this work in google chrome, neither the windows 10 mail client, nor the gmail service handler appears to respect this. The message ID's I have used were in the respective inboxes for both of these clients.

Is this feature actually supported by any mail clients or browsers?

Answer 1

Unfortunately it seems that this feature is not very widely supported. I tested a number of email clients including Outlook, Gmail and Mac OS, none of which appear to support it. The only email client that I have been able to find that supports the functionality is Thunderbird (which supports both the References and In-Reply-To headers).