diff --git a/modules/nixos/settings.nix b/modules/nixos/settings.nix
index 88cc0b4..2a1a218 100644
--- a/modules/nixos/settings.nix
+++ b/modules/nixos/settings.nix
@@ -40,5 +40,5 @@
   # enable home-manager globally
   home-manager.useGlobalPkgs = true;
   home-manager.useUserPackages = true;
-  home-manager.backupFileExtension = "backup";
+  home-manager.backupCommand = "mv -f {file} {file}.hm-bak-$(date +%Y%m%d%H%M%S)";
 }