diff --git a/nix/modules/customer-portal/default.nix b/nix/modules/customer-portal/default.nix
index fb46fe1..1d2c325 100755
--- a/nix/modules/customer-portal/default.nix
+++ b/nix/modules/customer-portal/default.nix
@@ -2,7 +2,7 @@
 let
   inherit (lib) mkEnableOption mkPackageOption mkOption mkIf types;
 
-  format = pkgs.json {};
+  format = pkgs.formats.json {};
 
   cfg = config.services.amarth-customer-portal;
 in