diff --git a/krebs/3modules/charybdis.nix b/krebs/3modules/charybdis.nix
index f4a7c1313..aa7c980c5 100644
--- a/krebs/3modules/charybdis.nix
+++ b/krebs/3modules/charybdis.nix
@@ -21,14 +21,14 @@ in
       enable = mkEnableOption "Charybdis IRC daemon";
 
       config = mkOption {
-        type = types.string;
+        type = types.str;
         description = ''
           Charybdis IRC daemon configuration file.
         '';
       };
 
       statedir = mkOption {
-        type = types.string;
+        type = types.str;
         default = "/var/lib/charybdis";
         description = ''
           Location of the state directory of charybdis.
@@ -36,7 +36,7 @@ in
       };
 
       user = mkOption {
-        type = types.string;
+        type = types.str;
         default = "ircd";
         description = ''
           Charybdis IRC daemon user.
@@ -44,7 +44,7 @@ in
       };
 
       group = mkOption {
-        type = types.string;
+        type = types.str;
         default = "ircd";
         description = ''
           Charybdis IRC daemon group.