diff --git a/deployments/seattle/flake.nix b/deployments/seattle/flake.nix
index 07a3d0b..a32bbf9 100644
--- a/deployments/seattle/flake.nix
+++ b/deployments/seattle/flake.nix
@@ -1,7 +1,9 @@
 {
   description = "Definition of the Seattle NixOps network.";
 
-  inputs = import ../../common/inputs.nix;
+  inputs = import ../../common/inputs.nix {
+    nixos-version = "21.05";
+  };
 
   outputs = { self, nixpkgs, fudo-nixos, ... } @ inputs:
     import ../../common/deployment.nix {