diff --git a/flake.lock b/flake.lock
index 50d000ce3..b7922587b 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,16 +2,16 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1636698608,
-        "narHash": "sha256-sxLLeQmH3UrP3UANqXzMLE0bPDgY5aIt04iBoPffG2E=",
+        "lastModified": 1637636156,
+        "narHash": "sha256-E2ym4Vcpqu9JYoQDXJZR48gVD+LPPbaCoYveIk7Xu3Y=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "92c881b6a72abce5bb2f5db3f903b4871d13aaa9",
+        "rev": "b026e1cf87a108dd06fe521f224fdc72fd0b013d",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "master",
+        "ref": "release-21.11",
         "repo": "nixpkgs",
         "type": "github"
       }
diff --git a/flake.nix b/flake.nix
index bcaa89708..0e89187fc 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,7 +1,7 @@
 {
   description = "The third-generation ARTIQ compiler";
 
-  inputs.nixpkgs.url = github:NixOS/nixpkgs/master;
+  inputs.nixpkgs.url = github:NixOS/nixpkgs/release-21.11;
 
   outputs = { self, nixpkgs }:
     let