diff --git a/flake.nix b/flake.nix
index 57f07ba..40669d5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -55,9 +55,18 @@
         ];
       };
 
+      latest-modified-timestamp = head
+        (sort (a: b: a > b)
+          (filter (timestamp: timestamp != null)
+            (map (input: toInt input.lastModifiedDate) inputs)));
+
+      concat-timestamp = timestamp:
+        toInt (substring 0 10 (toString timestamp));
+
       common-host-config = hostname: hostOpts: let
         config-dir = ./config;
-        build-timestamp = toInt fudo-entities.lastModifiedDate;
+        build-timestamp =
+          concatTimestamp last-modified-timestamp;
       in { config, ... }: {
         imports = [
           fudo-home.nixosModule