diff --git a/makefu/2configs/base-sources.nix b/makefu/2configs/base-sources.nix
index 7e6bebec3..65c6e8e76 100644
--- a/makefu/2configs/base-sources.nix
+++ b/makefu/2configs/base-sources.nix
@@ -1,6 +1,7 @@
 { config, lib, pkgs, ... }:
 
 {
+  system.stateVersion = "15.09";
   krebs.build.source = {
     git.nixpkgs = {
       #url = https://github.com/NixOS/nixpkgs;
diff --git a/makefu/2configs/unstable-sources.nix b/makefu/2configs/unstable-sources.nix
index f2d28dcaf..173060515 100644
--- a/makefu/2configs/unstable-sources.nix
+++ b/makefu/2configs/unstable-sources.nix
@@ -1,6 +1,7 @@
 { config, lib, pkgs, ... }:
 
 {
+  system.stateVersion = "15.09";
   krebs.build.source = {
     git.nixpkgs = {
       url = https://github.com/makefu/nixpkgs;