diff --git a/flake.lock b/flake.lock
index 07ee5a14c..13e10e611 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,19 +2,19 @@
   "inputs": {
     "nixpkgs": {
       "info": {
-        "lastModified": 1582018495,
-        "narHash": "sha256-xcpSl9tQKAsMQFmZfHXCqv6E9y1k6pk6T3i3jX1hsuk="
+        "lastModified": 1580555706,
+        "narHash": "sha256-ly5Gxl9yZgW2w1F3aDU5bvg34Ct+juUaOg8vue+Mkbo="
       },
       "inputs": {},
       "locked": {
-        "owner": "NixOS",
+        "owner": "edolstra",
         "repo": "nixpkgs",
-        "rev": "01d84d1ecfd50d809796176670448e0ec1cc4f5d",
+        "rev": "43e283790fbe330b723ac44b584824cf6d85c1ee",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "release-20.03",
+        "ref": "release-19.09",
         "type": "indirect"
       }
     }
diff --git a/flake.nix b/flake.nix
index 34e1e6ffb..078f51fa4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,7 +3,7 @@
 
   edition = 201909;
 
-  inputs.nixpkgs.uri = "nixpkgs/release-20.03";
+  inputs.nixpkgs.uri = "nixpkgs/release-19.09";
 
   outputs = { self, nixpkgs }:
 
@@ -72,7 +72,7 @@
             openssl pkgconfig sqlite
             libarchive
             boost
-            nlohmann_json
+            (nlohmann_json.override { multipleHeaders = true; })
             rustc cargo
 
             # Tests