The fundamental problem here is that this turns into a security problem, which in 2024 is not a nice thing to have.
Yes, theoretically I could run the previous Debian release, 11 Bullseye which is now EOL but in LTS until 2026.
However, the OpenSSL delivered with Bullseye is 1.1.1. Any LTS patches delivered by Debian are based on public patches, so basically there will be no OpenSSL patches because OpenSSL moved 1.1.1 to premium support only, *INCLUDING* security patches, as described on their website ("It will no longer be receiving publicly available security fixes after that date") https://www.openssl.org/blog/blog/2023/03/28/1.1.1-EOL/index.html.
Meanwhile, we are being spoonfed FUD/semi-FUD about the Debian provided 2.3 package. "be careful it's broken" is not a warning a good sysadmin takes lightly.
Meanwhile, if we're lucky, we might get 2.4 this side of Christmas 2024.
Its all a bit of a mess. Its all a bit worrying.
Meanwhile alternatives are few and far between, and I suspect Dovecot knows that ! The Dovecot community are left between the proverbial rock and a hard place.
Cyrus is now dependent on the commercial goodwill of FastMail, which brings thoughts of comparisons with Dovecot and OpenXChange.
Stalwart, whilst extraordinarily promising, needs another year or so of development to reach v1 and mature the code.