diff --git a/pkgs/development/python-modules/ics/default.nix b/pkgs/development/python-modules/ics/default.nix
index c347b177587c..2f973a6dc981 100644
--- a/pkgs/development/python-modules/ics/default.nix
+++ b/pkgs/development/python-modules/ics/default.nix
@@ -16,7 +16,7 @@ buildPythonPackage rec {
   version = "0.7.2";
   pyproject = true;
 
-  disabled = pythonOlder "3.6";
+  disabled = pythonOlder "3.7";
 
   src = fetchFromGitHub {
     owner = "ics-py";
@@ -25,9 +25,14 @@ buildPythonPackage rec {
     hash = "sha256-hdtnET7YfSb85+TGwpwzoxOfxPT7VSj9eKSiV6AXUS8=";
   };
 
-  nativeBuildInputs = [ setuptools ];
+  postPatch = ''
+    substituteInPlace setup.cfg \
+      --replace-fail "--pep8" ""
+  '';
 
-  propagatedBuildInputs = [
+  build-system = [ setuptools ];
+
+  dependencies = [
     attrs
     arrow
     tatsu
@@ -38,18 +43,13 @@ buildPythonPackage rec {
     pytestCheckHook
   ];
 
-  postPatch = ''
-    # 0.8 will move to python-dateutil
-    substituteInPlace requirements.txt \
-      --replace "arrow>=0.11,<0.15" "arrow"
-    substituteInPlace setup.cfg --replace "--pep8" ""
-  '';
-
   disabledTests = [
     # Failure seems to be related to arrow > 1.0
     "test_event"
     # Broke with TatSu 5.7:
     "test_many_lines"
+    # AssertionError: 'Europe/Berlin' not found in "tzfile('Atlantic/Jan_Mayen')"
+    "test_timezone_not_dropped"
   ];
 
   pythonImportsCheck = [ "ics" ];