Add an option to include the forwarding address in the header "To:" field or subject line #2702
Description
Problem Statement:
It's useful to include +tags in forwarding email addresses (aka SimpleLogin Mailboxes) for downstream mail filter rules to organize incoming mail. For example, given the following aliases:
- [email protected] & [email protected] -> [email protected]
- [email protected] & [email protected] -> [email protected]
iCloud mail rules could then automatically file messages containing "+retail" into a "Retail" folder, and "+news" into a "News" folder.
Except this doesn't work because (1) SimpleLogin only includes the forwarding address in the envelope-to field, not the header-to field, and (2) downstream filter rules (for iCloud and most other email services) only look at the header-to field, not the envelope-to field. Therefore, +tags in forwarding addresses aren't visible to downstream filter rules. :-(
Requested Solution:
Enhance SimpleLogin to include the forwarding address into either the header-to field or the subject field, so it can be detected and acted upon by downstream filter rules. This can be implemented multiple ways, and any of the following approaches would solve this use case:
- Set the header-to field to the forwarding address rather than the original (alias) address, e.g. use "John Doe [email protected]" rather than "John Doe [email protected]"
- Append the forwarding address to the Display Name section of the header-to field, e.g. "John Doe ([email protected]) [email protected]"
- Append the forwarding address to the subject field, e.g. "[[email protected]] Original subject line"
This could be implemented as an optional feature that's off by default, and enabled per Mailbox or globally across all Mailboxes. (Just don't require it to be enabled per Alias, as that would be too messy and error-prone.)
Note that Proton Mail does support filtering on envelope fields, but only when using custom sieve scripts (via: if envelope :contains "to" "XXX" { ... }), which is fairly advanced for most users. Proton's default (non-Sieve) rules don't support envelopes, nor do iCloud or most other email services. Therefore, it would be a tremendous benefit for SimpleLogin to include the forwarding address into filterable mail fields.
Thank you for your consideration. :-)