diff --git a/packages/@jsii/python-runtime/requirements.txt b/packages/@jsii/python-runtime/requirements.txt
index fc017b6e0b..4a7023ebf4 100644
--- a/packages/@jsii/python-runtime/requirements.txt
+++ b/packages/@jsii/python-runtime/requirements.txt
@@ -1,5 +1,5 @@
 black~=25.1
-mypy==1.15.0
+mypy==1.17.1
 pip~=25.1
 pytest~=8.4
 pytest-mypy~=1.0
diff --git a/packages/@jsii/python-runtime/tests/test_compliance.py b/packages/@jsii/python-runtime/tests/test_compliance.py
index 051fabb76f..589c33f9e4 100644
--- a/packages/@jsii/python-runtime/tests/test_compliance.py
+++ b/packages/@jsii/python-runtime/tests/test_compliance.py
@@ -884,11 +884,11 @@ def private_property(self):
 def test_doNotOverridePrivates_property_getter():
     class TDoNotOverridePrivates(DoNotOverridePrivates):
         @property
-        def private_property(self):
+        def private_property(self) -> str:
             return "privateProperty-Override"
 
         @private_property.setter
-        def private_property(self):
+        def private_property(self, _: str):
             raise RuntimeError("Boom")
 
     obj = TDoNotOverridePrivates()
diff --git a/packages/@jsii/python-runtime/tests/test_invoke_bin.py b/packages/@jsii/python-runtime/tests/test_invoke_bin.py
index d9a17e52bd..fb11994fbe 100644
--- a/packages/@jsii/python-runtime/tests/test_invoke_bin.py
+++ b/packages/@jsii/python-runtime/tests/test_invoke_bin.py
@@ -94,9 +94,7 @@ def test_invoke_script_with_line_flush(
         buffered to the end
         """
         script_path = f".env/bin/calc"
-        proc = subprocess.Popen(
-            [script_path, "arg1", "delay"], stdout=subprocess.PIPE, bufsize=1
-        )
+        proc = subprocess.Popen([script_path, "arg1", "delay"], stdout=subprocess.PIPE)
 
         timed_lines = []
         last_dt = None