diff --git a/osclib/stagingapi.py b/osclib/stagingapi.py
index 83b2ced9..92f2d9cd 100644
--- a/osclib/stagingapi.py
+++ b/osclib/stagingapi.py
@@ -881,7 +881,7 @@ class StagingAPI(object):
         """
         freezetime = attribute_value_load(self.apiurl, project, 'FreezeTime')
         if freezetime:
-            freezetime = datetime.fromisoformat(freezetime)
+            freezetime = dateutil.parser.isoparse(freezetime)
             tz_info = freezetime.tzinfo
             return (datetime.now(tz_info) - freezetime).total_seconds() / 3600 / 24
         # fallback: old method
diff --git a/tests/OBSLocal.py b/tests/OBSLocal.py
index 1f5d725e..3d838ec4 100644
--- a/tests/OBSLocal.py
+++ b/tests/OBSLocal.py
@@ -152,7 +152,7 @@ class TestCase(unittest.TestCase):
         try:
             env = os.environ
             env['OSC_CONFIG'] = OSCRC
-            self.output = subprocess.check_output(args, stderr=subprocess.STDOUT, text=True, env=env)
+            self.output = subprocess.check_output(args, stderr=subprocess.STDOUT, universal_newlines=True, env=env)
         except subprocess.CalledProcessError as e:
             print(e.output)
             raise e