1 files changed, 3 insertions, 3 deletions
diff --git a/modules/by-name/st/stalwart-mail/module.nix b/modules/by-name/st/stalwart-mail/module.nix
index ae3ccea..1e39e81 100644
--- a/modules/by-name/st/stalwart-mail/module.nix
+++ b/modules/by-name/st/stalwart-mail/module.nix
@@ -41,8 +41,8 @@ in {
     };
 
     principals = lib.mkOption {
-      default = [];
-      type = lib.types.listOf (lib.types.submodule {
+      default = null;
+      type = lib.types.nullOr (lib.types.listOf (lib.types.submodule {
         options = {
           name = lib.mkOption {
             type = lib.types.str;
@@ -77,7 +77,7 @@ in {
             '';
           };
         };
-      });
+      }));
     };
 
     dataDirectory = lib.mkOption {