diff --git a/brainstate/nn/__init__.py b/brainstate/nn/__init__.py
index af2fa80..a933ecb 100644
--- a/brainstate/nn/__init__.py
+++ b/brainstate/nn/__init__.py
@@ -358,7 +358,6 @@
     'LIFRef': 'brainpy.state.LIFRef',
     'ALIF': 'brainpy.state.ALIF',
     'LeakyRateReadout': 'brainpy.state.LeakyRateReadout',
-    'LeakySpikeReadout': 'brainpy.state.LeakySpikeReadout',
     'STP': 'brainpy.state.STP',
     'STD': 'brainpy.state.STD',
     'Synapse': 'brainpy.state.Synapse',
diff --git a/brainstate/nn/_utils_test.py b/brainstate/nn/_utils_test.py
index e48d6a3..cc3dc67 100644
--- a/brainstate/nn/_utils_test.py
+++ b/brainstate/nn/_utils_test.py
@@ -555,6 +555,15 @@ def test_deprecated_name_forwards_to_brainpy(self):
         self.assertIs(obj, brainpy.state.IF)
         self.assertTrue(any(issubclass(w.category, DeprecationWarning) for w in caught))
 
+    def test_every_deprecated_name_resolves_in_brainpy(self):
+        """Every ``_DEPRECATED_NAMES`` target exists in ``brainpy.state``."""
+        brainpy = pytest.importorskip("brainpy", exc_type=ImportError)
+        from brainstate.nn import _DEPRECATED_NAMES
+        for name, target in _DEPRECATED_NAMES.items():
+            with self.subTest(name=name):
+                self.assertEqual(target, f'brainpy.state.{name}')
+                self.assertTrue(hasattr(brainpy.state, name))
+
     def test_unknown_attribute_raises(self):
         """An unrecognized attribute raises ``AttributeError``."""
         with self.assertRaises(AttributeError):
diff --git a/requirements-dev.txt b/requirements-dev.txt
index ba0697f..84bc20a 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -5,7 +5,7 @@ numba
 braintools>=0.3.0
 braincell
 matplotlib
-brainpy-state
+brainpy>=2.9.0
 
 # test requirements
 pytest