diff --git a/devshells/markdown.nix b/devshells/markdown.nix
index 70cf92e..cb7b3ed 100644
--- a/devshells/markdown.nix
+++ b/devshells/markdown.nix
@@ -1,6 +1,7 @@
 {
   withSystem,
   inputs,
+  inputs',
   ...
 }: {
   perSystem = {
@@ -11,13 +12,12 @@
     ...
   }: {
     devShells.markdown = pkgs.mkShell {
-      buildInputs = with pkgs; [
+      buildInputs = with inputs'.nixpkgs-unstable.legacyPackages; [
         (python3.withPackages (ps:
           with ps; [
             mdformat
             mdformat-gfm
-            # TODO: Broken?
-            # mdformat-gfm-alerts
+            mdformat-gfm-alerts
             mdformat-tables
             mdformat-footnote
             pygments
diff --git a/flake.lock b/flake.lock
index 6e31a38..e3573da 100644
--- a/flake.lock
+++ b/flake.lock
@@ -210,11 +210,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1751011381,
-        "narHash": "sha256-krGXKxvkBhnrSC/kGBmg5MyupUUT5R6IBCLEzx9jhMM=",
+        "lastModified": 1751637120,
+        "narHash": "sha256-xVNy/XopSfIG9c46nRmPaKfH1Gn/56vQ8++xWA8itO4=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "30e2e2857ba47844aa71991daa6ed1fc678bcbb7",
+        "rev": "5c724ed1388e53cc231ed98330a60eb2f7be4be3",
         "type": "github"
       },
       "original": {