diff --git a/flake.lock b/flake.lock
index a0eacbd..2c0a8e2 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1792502884,
-        "narHash": "sha256-IoNisKcGbUjdd45qCqywGMCYmZ5EnkxezvLII0FWwNA=",
+        "lastModified": 1793341285,
+        "narHash": "sha256-Y1CiZ4SoBUjLQyQM/pY+rS2dXD3CHLPstF0lmOc73D4=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "02c087f3fe673c9e317f206a627cb6b910336dbe",
+        "rev": "1c89083e451e891152365b799595cf7790a43325",
         "type": "github"
       },
       "original": {
diff --git a/nix/develop/flake.lock b/nix/develop/flake.lock
index f91b94e..9afa60e 100644
--- a/nix/develop/flake.lock
+++ b/nix/develop/flake.lock
@@ -89,11 +89,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1792502884,
-        "narHash": "sha256-IoNisKcGbUjdd45qCqywGMCYmZ5EnkxezvLII0FWwNA=",
+        "lastModified": 1793341285,
+        "narHash": "sha256-Y1CiZ4SoBUjLQyQM/pY+rS2dXD3CHLPstF0lmOc73D4=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "02c087f3fe673c9e317f206a627cb6b910336dbe",
+        "rev": "1c89083e451e891152365b799595cf7790a43325",
         "type": "github"
       },
       "original": {
@@ -122,11 +122,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1792739799,
-        "narHash": "sha256-M2rr/yPbTHvgAzCyZ+zHJHflFM0XU7t42Sw2skA3TQM=",
+        "lastModified": 1793348683,
+        "narHash": "sha256-qv+P8z2xS5Xdws5Kigvr/WKJiaJSa6Ke8iH7ozmO53w=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "b0829a2cc9f7b596583331d78a942c1e5170d8a0",
+        "rev": "96a0986b0486341fbc163fa2fabc6d3b44cdcbf1",
         "type": "github"
       },
       "original": {
diff --git a/nix/develop/flake.nix b/nix/develop/flake.nix
index e095f0a..1659050 100644
--- a/nix/develop/flake.nix
+++ b/nix/develop/flake.nix
@@ -75,6 +75,14 @@
         };
       flake.githubActions = inputs.nix-github-actions.lib.mkGithubMatrix {
         checks = self.checks;
+        # nix-github-actions pins aarch64-darwin to the retired macos-14. Only
+        # x86_64-linux and macOS arm64 have a moving "-latest" label; arm64 Linux
+        # has none, so it stays pinned.
+        platforms = {
+          x86_64-linux = "ubuntu-latest";
+          aarch64-linux = "ubuntu-24.04-arm";
+          aarch64-darwin = "macos-latest";
+        };
       };
     };
 }