`sslCACert` was used for trust store of client and server certificates. Since `smtpd_tls_ask_ccert` defaults to no the setup of `smtpd_tls_CApath` was removed. >By default (see smtpd_tls_ask_ccert), client certificates are not requested, and smtpd_tls_CApath should remain empty. see http://www.postfix.org/postconf.5.html#smtpd_tls_CAfile
To build the manual, you need Nix installed on your system (no need
for NixOS). To install Nix, follow the instructions at
https://nixos.org/nix/download.html
When you have Nix on your system, in the root directory of the project
(i.e., `nixpkgs`), run:
nix-build nixos/release.nix -A manual.x86_64-linux
When this command successfully finishes, it will tell you where the
manual got generated.