diff --git a/nix/overlay.nix b/nix/overlay.nix
index ff97c8b..de75f52 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -1,10 +1,19 @@
+self: super:
+
 let
   nixpkgs-master = import (builtins.fetchTarball {
     url = "https://github.com/NixOS/nixpkgs-channels/archive/de5fd9e6110489722e8667664dce9fdc17331866.tar.gz";
     sha256 = "0z1j2pmvn15m2ir2i9l2prr81cq7f1x8xs4cv2s7q4fslz586ghn";
   }) {};
+  # one application requires php5
+  nixpkgsWithPhp5 = super.fetchFromGitHub {
+    owner = "nixos";
+    repo = "nixpkgs-channels";
+    rev = "846d8f8305192dcc3a63139102698b4ac6b9ef9f";
+    sha256 = "1qifgc1q2i4g0ivpfjnxp4jl2cc82gfjws08dsllgw7q7kw4b4rb";
+  };
 
-in self: super: {
+in {
   podman = nixpkgs-master.podman;
   conmon = nixpkgs-master.conmon;
 
@@ -25,4 +34,18 @@ in self: super: {
   dropbearStatic = super.dropbear.override {
     enableStatic = true;
   };
+
+  php56 = (super.callPackages
+    "${nixpkgsWithPhp5}/pkgs/development/interpreters/php/default.nix" {})
+    .php56.overrideAttrs(drv: rec {
+      # See https://secure.php.net/ChangeLog-5.php
+      version = "5.6.40";
+      name = "php-${version}";
+
+      sha256 = "005s7w167dypl41wlrf51niryvwy1hfv53zxyyr3lm938v9jbl7z";
+      src = super.fetchurl {
+        url = "http://www.php.net/distributions/php-${version}.tar.bz2";
+        inherit sha256;
+      };
+    });
 }