Feature/configurable delimiter

default.nix

@@ -620,6 +620,14 @@ in
       '';
     };
 
+    recipientDelimiter = mkOption {
+      type = types.str;
+      default = "+";
+      description = ''
+        Configure the recipient delimiter.
+      '';
+    };
+
     redis = {
       address = mkOption {
         type = types.str;

mail-server/dovecot.nix

@@ -191,7 +191,7 @@ in
           }
         }
 
-        recipient_delimiter = +
+        recipient_delimiter = ${cfg.recipientDelimiter}
         lmtp_save_to_detail_mailbox = ${cfg.lmtpSaveToDetailMailbox}
 
         protocol lmtp {

mail-server/postfix.nix

@@ -160,7 +160,7 @@ in
       config = {
         # Extra Config
         mydestination = "";
-        recipient_delimiter = "+";
+        recipient_delimiter = cfg.recipientDelimiter;
         smtpd_banner = "${fqdn} ESMTP NO UCE";
         disable_vrfy_command = true;
         message_size_limit = toString cfg.messageSizeLimit;