I was hoping to use inet_listener_address to specify different listening addresses for IMAP (143) and IMAPS (993).

It looks like inet_listener_address appears in the documentation[1] but is unimplemented[2].

1. https://doc.dovecot.org/2.4.2/core/config/service.html#inet_listener_address
2. https://github.com/dovecot/core/blob/13ac9959a3c399e8a9d53f40f7858109dc0801f3/src/lib-master/service-settings.h#L43-L52

(I have sent this in as an issue on the mailing list)