diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index f60b20dd8527..01fa32e397c3 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -66,6 +66,10 @@
 /doc/build-helpers/images/makediskimage.section.md  @raitobezarius
 /nixos/lib/make-disk-image.nix                 @raitobezarius
 
+# Nix, the package manager
+pkgs/tools/package-management/nix/                    @raitobezarius
+nixos/modules/installer/tools/nix-fallback-paths.nix  @raitobezarius
+
 # Nixpkgs documentation
 /maintainers/scripts/db-to-md.sh @jtojnar @ryantm
 /maintainers/scripts/doc @jtojnar @ryantm
diff --git a/nixos/modules/installer/tools/nix-fallback-paths.nix b/nixos/modules/installer/tools/nix-fallback-paths.nix
index d1cdef213551..e4241e965403 100644
--- a/nixos/modules/installer/tools/nix-fallback-paths.nix
+++ b/nixos/modules/installer/tools/nix-fallback-paths.nix
@@ -1,7 +1,7 @@
 {
-  x86_64-linux = "/nix/store/smfmnz0ylx80wkbqbjibj7zcw4q668xp-nix-2.19.2";
-  i686-linux = "/nix/store/knp0akbpj2k0rf26fmysmxdysmayihax-nix-2.19.2";
-  aarch64-linux = "/nix/store/761hq0abn07nrydrf6mls61bscx2vz2i-nix-2.19.2";
-  x86_64-darwin = "/nix/store/zlqvxis1dfcfgmy5fza4hllg6h03vhpb-nix-2.19.2";
-  aarch64-darwin = "/nix/store/53r8ay20mygy2sifn7j2p8wjqlx2kxik-nix-2.19.2";
+  x86_64-linux = "/nix/store/azvn85cras6xv4z5j85fiy406f24r1q0-nix-2.18.1";
+  i686-linux = "/nix/store/9bnwy7f9h0kzdzmcnjjsjg0aak5waj40-nix-2.18.1";
+  aarch64-linux = "/nix/store/hh65xwqm9s040s3cgn9vzcmrxj0sf5ij-nix-2.18.1";
+  x86_64-darwin = "/nix/store/6zi5fqzn9n17wrk8r41rhdw4j7jqqsi3-nix-2.18.1";
+  aarch64-darwin = "/nix/store/0pbq6wzr2f1jgpn5212knyxpwmkjgjah-nix-2.18.1";
 }
diff --git a/pkgs/tools/package-management/nix/default.nix b/pkgs/tools/package-management/nix/default.nix
index 411030ee5733..4652ddb76a5b 100644
--- a/pkgs/tools/package-management/nix/default.nix
+++ b/pkgs/tools/package-management/nix/default.nix
@@ -259,7 +259,7 @@ in lib.makeExtensible (self: ({
     else
       nix;
 
-  stable = addFallbackPathsCheck self.nix_2_19;
+  stable = addFallbackPathsCheck self.nix_2_18;
 
   unstable = self.nix_2_19;
 } // lib.optionalAttrs config.allowAliases {