diff --git a/configuration.nix b/configuration.nix
index fc8365f..ad22b24 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -78,7 +78,9 @@
     "# Completely remove remnants of NIXOS_LUSTRATE."
     "R! /old-root"
   ];
-  system.stateVersion = config.selfprivacy.stateVersion;
+  system.stateVersion =
+    lib.mkIf (config.selfprivacy.stateVersion != null)
+      config.selfprivacy.stateVersion;
   system.autoUpgrade = {
     enable = config.selfprivacy.autoUpgrade.enable;
     allowReboot = config.selfprivacy.autoUpgrade.allowReboot;
diff --git a/selfprivacy-module.nix b/selfprivacy-module.nix
index 268153a..b0fa077 100644
--- a/selfprivacy-module.nix
+++ b/selfprivacy-module.nix
@@ -36,7 +36,8 @@ with lib;
     };
     stateVersion = mkOption {
       description = "State version of the server";
-      type = types.str;
+      type = types.nullOr types.str;
+      default = null;
     };
     ########################
     # Server admin options #