diff --git a/flake.lock b/flake.lock
index 07f0ad3..907d1cb 100644
--- a/flake.lock
+++ b/flake.lock
@@ -68,16 +68,16 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1642492175,
-        "narHash": "sha256-lo5hxiY8U4eREChAR7JD94zns92hQqmp3wg3qTFolPA=",
+        "lastModified": 1643080866,
+        "narHash": "sha256-iO3Z6jw0HEiie8UnXVpq1SxphprDYBXrVzubEa5D4eE=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "9789ed45b759c8f770bcba4b06c1a1c5ec386664",
+        "rev": "c07b471b52be8fbc49a7dc194e9b37a6e19ee04d",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
+        "ref": "nixos-unstable",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -87,9 +87,26 @@
         "flake-compat": "flake-compat",
         "nix-eval-jobs": "nix-eval-jobs",
         "nixpkgs": "nixpkgs_2",
+        "stable": "stable",
         "utils": "utils"
       }
     },
+    "stable": {
+      "locked": {
+        "lastModified": 1642961095,
+        "narHash": "sha256-RLatktZmvwFBOyqdoIk4qdS4OGKB7aKIvvs4ZP2L8D8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "604c44137d97b5111be1ca5c0d97f6e24fbc5c2c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "utils": {
       "locked": {
         "lastModified": 1638122382,
diff --git a/flake.nix b/flake.nix
index 98d39a4..b04e551 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,7 +2,9 @@
   description = "A simple, stateless NixOS deployment tool modeled after NixOps.";
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    stable.url = "github:NixOS/nixpkgs/nixos-21.11";
+
     utils.url = "github:numtide/flake-utils";
 
     # not yet upstreamed
diff --git a/integration-tests/default.nix b/integration-tests/default.nix
index 1341f3c..a7450d8 100644
--- a/integration-tests/default.nix
+++ b/integration-tests/default.nix
@@ -7,4 +7,10 @@
   flakes = import ./flakes {};
   flakes-streaming = import ./flakes { evaluator = "streaming"; };
   parallel = import ./parallel {};
+
+  apply-stable = let
+    test = import ./apply { pkgs = import ./nixpkgs-stable.nix; };
+  in test.override (old: {
+    name = "apply-stable";
+  });
 }
diff --git a/integration-tests/nixpkgs-stable.nix b/integration-tests/nixpkgs-stable.nix
new file mode 100644
index 0000000..a23282b
--- /dev/null
+++ b/integration-tests/nixpkgs-stable.nix
@@ -0,0 +1,8 @@
+let
+  flake = (import ../flake-compat.nix).defaultNix;
+in import flake.inputs.stable.outPath {
+  overlays = [
+    flake._evalJobsOverlay
+    flake.overlay
+  ];
+}
diff --git a/integration-tests/tools.nix b/integration-tests/tools.nix
index 1a4be9c..51552c5 100644
--- a/integration-tests/tools.nix
+++ b/integration-tests/tools.nix
@@ -174,7 +174,7 @@ let
     } // test // {
       testScript = fullScript;
     };
-  in pkgs.nixosTest combined;
+  in lib.makeOverridable pkgs.nixosTest combined;
 in {
   inherit pkgs nodes colmena colmenaExec
     getStandaloneConfigFor inputClosureOf makeTest;