diff --git a/nix/overlays/haskell-packages.nix b/nix/overlays/haskell-packages.nix
index 16a25bf0fab..716664e0b5d 100644
--- a/nix/overlays/haskell-packages.nix
+++ b/nix/overlays/haskell-packages.nix
@@ -19,15 +19,18 @@ let
       #
       # To temporarily pin unreleased versions from GitHub:
       #   <name> =
-      #     prev.callCabal2nixWithOptions "<name>" (super.fetchFromGitHub {
+      #     lib.dontCheck (prev.callCabal2nixWithOptions "<name>" (super.fetchFromGitHub {
       #       owner = "<owner>";
       #       repo  = "<repo>";
       #       rev = "<commit>";
       #       sha256 = "<sha256>";
-      #    }) "--subpath=<subpath>" {};
+      #    }) "--subpath=." {});
       #
       # To fill in the sha256:
       #   update-nix-fetchgit nix/overlays/haskell-packages.nix
+      #
+      # Nowadays you can just delete the sha256 attribute above and nix will assume a fake sha.
+      # Once you build the derivation it will suggest the correct sha.
 
       configurator-pg =
         prev.callHackageDirect
@@ -48,6 +51,14 @@ let
 
       hasql-pool = lib.dontCheck prev.hasql-pool_0_10;
 
+      hasql-notifications = lib.dontCheck (prev.callCabal2nixWithOptions "hasql-notifications"
+      (super.fetchFromGitHub {
+         owner = "diogob";
+         repo  = "hasql-notifications";
+         rev = "769ca47f4da421b75b97a87102613b406d46d0d3";
+         sha256 = "sha256-Z/FqwPaVvj0kUYyK7lsQ1WA5WmXi5nx5kSnZjBtpg8Q=";
+      }) "--subpath=." {});
+
     };
 in
 {