diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 88c5440..340b54d 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -44,7 +44,7 @@ jobs:
             oldest_installer_version: nix-2.8.0
           - runs-on: macos-15-intel
             system: x86_64-darwin
-            oldest_installer_version: nix-2.18.0
+            oldest_installer_version: nix-2.18.6
           # macos13 will be retired on 04/12/2025
           - runs-on: macos-13
             system: x86_64-darwin