diff --git a/pkgs/applications/networking/powerdns-admin/default.nix b/pkgs/applications/networking/powerdns-admin/default.nix
index 8ea5c4904f119..f87fc455f9b8e 100644
--- a/pkgs/applications/networking/powerdns-admin/default.nix
+++ b/pkgs/applications/networking/powerdns-admin/default.nix
@@ -15,8 +15,11 @@ let
         version = "1.16.0";
         src = oldAttrs.src.override {
           inherit version;
+          extension = "zip";
           sha256 = "36c5e8e38d4369a08b6780b7f27d790a292b2b08eea01607865bf0936c558e01";
         };
+        # Needs networking for some tests
+        doCheck = false;
       });
     };
   };
diff --git a/pkgs/development/python-modules/bravado-core/default.nix b/pkgs/development/python-modules/bravado-core/default.nix
index 24db42b7a74f5..7db990fdc98a5 100644
--- a/pkgs/development/python-modules/bravado-core/default.nix
+++ b/pkgs/development/python-modules/bravado-core/default.nix
@@ -1,8 +1,32 @@
-{ lib, buildPythonPackage, fetchFromGitHub, python-dateutil, jsonref, jsonschema,
+{ lib, buildPythonPackage, fetchFromGitHub, fetchPypi, python-dateutil, jsonref, jsonschema,
   pyyaml, simplejson, six, pytz, msgpack, swagger-spec-validator, rfc3987,
   strict-rfc3339, webcolors, mypy-extensions, jsonpointer, idna, pytest, mock,
   pytest-benchmark, isPy27, enum34 }:
 
+let
+  jsonschema320 = jsonschema.overridePythonAttrs (oldAttrs: rec {
+    version = "3.2.0";
+
+    src = fetchPypi {
+      inherit (oldAttrs) pname;
+      inherit version;
+      hash = "sha256-yKhbKNN3zHc35G4tnytPRO48Dh3qxr9G3e/HGH0weXo=";
+    };
+
+    SETUPTOOLS_SCM_PRETEND_VERSION = version;
+
+    doCheck = false;
+  });
+
+  swagger-spec-validator' = swagger-spec-validator.overridePythonAttrs (oldAttrs: rec {
+    propagatedBuildInputs = [
+      pyyaml
+      jsonschema320
+      six
+    ];
+  });
+in
+
 buildPythonPackage rec {
   pname = "bravado-core";
   version = "5.17.0";
@@ -26,13 +50,13 @@ buildPythonPackage rec {
   propagatedBuildInputs = [
     python-dateutil
     jsonref
-    jsonschema
+    jsonschema320
     pyyaml
     simplejson
     six
     pytz
     msgpack
-    swagger-spec-validator
+    swagger-spec-validator'
 
     # the following 3 packages are included when jsonschema (3.2) is installed
     # as jsonschema[format], which reflects what happens in setup.py