diff --git a/flake.lock b/flake.lock
index 97160410f5..a59da9a640 100644
--- a/flake.lock
+++ b/flake.lock
@@ -98,11 +98,11 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1628085532,
-        "narHash": "sha256-X639O/RVYRdasl+nYR80KCn5OqTNdeDfvsYECtSZVLQ=",
+        "lastModified": 1633329294,
+        "narHash": "sha256-0LpQLS4KMgxslMgmDHmxG/5twFlXDBW9z4Or1iOrCvU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f6ccdfcd2ac4f2e259d20e378737dcbd0ca7debe",
+        "rev": "ee084c02040e864eeeb4cf4f8538d92f7c675671",
         "type": "github"
       },
       "original": {
diff --git a/nix/packages.nix b/nix/packages.nix
index 440d521ee1..2d53def08f 100644
--- a/nix/packages.nix
+++ b/nix/packages.nix
@@ -5,7 +5,7 @@ let
     ${nix.defaultPackage.${system}}/bin/nix --experimental-features 'nix-command flakes' --extra-substituters https://lean4.cachix.org/ --option warn-dirty false "$@"
   '';
   # https://github.com/NixOS/nixpkgs/issues/130963
-  llvmPackages = if stdenv.isDarwin then llvmPackages_11 else llvmPackages_12;
+  llvmPackages = if stdenv.isDarwin then llvmPackages_11 else llvmPackages_13;
   cc = (ccacheWrapper.override rec {
     cc = llvmPackages.clang;
     extraConfig = ''
@@ -72,7 +72,7 @@ let
     src = mdBook;
     cargoDeps = drv.cargoDeps.overrideAttrs (_: {
       inherit src;
-      outputHash = "sha256-GFjy0bkPql/694F3y+mDtUy526IbO3anInVKFeBxlUc=";
+      outputHash = "sha256-fowNVGhul0jniLmEAt5O/ZrvabuEe02uOAM4S/CB9ss=";
     });
     doCheck = false;
   });