diff --git a/python/__init__.py b/python/__init__.py
index 1de3ff400..9fa3dcfe2 100644
--- a/python/__init__.py
+++ b/python/__init__.py
@@ -21,6 +21,7 @@
 import atexit
 import sys
 import ctypes
+import inspect
 from time import gmtime, struct_time
 import os
 from typing import Mapping, Optional
@@ -103,6 +104,13 @@
 	from .firmwareninja import *
 
 
+def _get_parameter_count(callback):
+	if sys.version_info >= (3, 14):
+		import annotationlib
+		return len(inspect.signature(callback, annotation_format=annotationlib.Format.STRING).parameters)
+	return len(inspect.signature(callback).parameters)
+
+
 def shutdown():
 	"""
 	``shutdown`` cleanly shuts down the core, stopping all workers and closing all log files.
diff --git a/python/demangle.py b/python/demangle.py
index 4b8e77704..326d018fa 100644
--- a/python/demangle.py
+++ b/python/demangle.py
@@ -19,7 +19,6 @@
 # IN THE SOFTWARE.
 
 import ctypes
-import inspect
 import warnings
 
 # Binary Ninja components
@@ -445,6 +444,7 @@ class Demangler(metaclass=_DemanglerMetaclass):
 	_cached_name = None
 
 	def __init__(self, handle=None):
+		self._uses_legacy_demangle_signature = False
 		if handle is not None:
 			self.handle = core.handle_of_type(handle, core.BNDemangler)
 			self.__dict__["name"] = core.BNGetDemanglerName(handle)
@@ -464,6 +464,22 @@ def register(cls):
 		assert demangler.__class__.name is not None
 		assert demangler.handle is None
 
+		try:
+			parameter_count = binaryninja._get_parameter_count(demangler.demangle)
+		except (TypeError, ValueError):
+			parameter_count = 2
+		demangler._uses_legacy_demangle_signature = parameter_count == 3
+		if demangler._uses_legacy_demangle_signature:
+			warnings.warn(
+				deprecation.DeprecatedWarning(
+					"Custom Demangler.demangle(arch, name, view)",
+					"5.4",
+					None,
+					"Use Demangler.demangle(name, config) instead."
+				),
+				stacklevel=2
+			)
+
 		demangler._cb = core.BNDemanglerCallbacks()
 		demangler._cb.context = 0
 		demangler._cb.isMangledString = demangler._cb.isMangledString.__class__(demangler._is_mangled_string)
@@ -518,18 +534,7 @@ def _demangle(self, ctxt, name, config, result):
 			api_config = DemanglerConfig._from_core_struct(config)
 
 			demangle = self.demangle
-			try:
-				parameter_count = len(inspect.signature(demangle).parameters)
-			except (TypeError, ValueError):
-				parameter_count = 2
-
-			if parameter_count == 3:
-				warnings.warn(
-					"Custom Demangler.demangle(arch, name, view) is deprecated; "
-					"use Demangler.demangle(name, config)",
-					DeprecationWarning,
-					stacklevel=2
-				)
+			if self._uses_legacy_demangle_signature:
 				arch = api_config.platform.arch if api_config.platform is not None else None
 				demangle_result = demangle(arch, core.pyNativeStr(name), api_config.view)
 			else: