diff --git a/flake.nix b/flake.nix
index 8f6f430..28131b6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -95,7 +95,10 @@
               # Pull from the workspace Cargo.toml — the per-crate
               # manifests use `version.workspace = true` which evaluates
               # to a table here, not a string.
-              version = (builtins.fromTOML (builtins.readFile ./Cargo.toml)).workspace.package.version;
+              version =
+                (builtins.fromTOML (builtins.readFile ./Cargo.toml)).workspace.package.version
+                + "-"
+                + (toString self.lastModifiedDate);
 
               src = ./.;