diff --git a/pkgs/development/python-modules/aiosasl/default.nix b/pkgs/development/python-modules/aiosasl/default.nix
index 81f96c4d1b1b..fe977cc1bbec 100644
--- a/pkgs/development/python-modules/aiosasl/default.nix
+++ b/pkgs/development/python-modules/aiosasl/default.nix
@@ -5,13 +5,16 @@
   fetchpatch,
   pyopenssl,
   pytestCheckHook,
+  pythonOlder,
+  setuptools,
 }:
 
 buildPythonPackage rec {
   pname = "aiosasl";
   version = "0.5.0";
+  pyproject = true;
 
-  format = "setuptools";
+  disabled = pythonOlder "3.7";
 
   src = fetchFromGitHub {
     owner = "horazont";
@@ -28,6 +31,14 @@ buildPythonPackage rec {
     })
   ];
 
+  postPatch = ''
+    # https://github.com/horazont/aiosasl/issues/28
+    substituteInPlace tests/test_aiosasl.py \
+      --replace-fail "assertRaisesRegexp" "assertRaisesRegex"
+  '';
+
+  build-system = [ setuptools ];
+
   nativeCheckInputs = [
     pyopenssl
     pytestCheckHook