diff -upr pyside-setup-opensource-src-5.15.2.orig/sources/shiboken2/libshiboken/pep384impl.cpp pyside-setup-opensource-src-5.15.2/sources/shiboken2/libshiboken/pep384impl.cpp
--- pyside-setup-opensource-src-5.15.2.orig/sources/shiboken2/libshiboken/pep384impl.cpp	2020-11-11 14:51:30.000000000 +0200
+++ pyside-setup-opensource-src-5.15.2/sources/shiboken2/libshiboken/pep384impl.cpp	2021-12-01 15:17:21.444888977 +0200
@@ -751,7 +751,7 @@ _Pep_PrivateMangle(PyObject *self, PyObj
 #endif // IS_PY2
     Shiboken::AutoDecRef privateobj(PyObject_GetAttr(
         reinterpret_cast<PyObject *>(Py_TYPE(self)), Shiboken::PyMagicName::name()));
-#ifndef Py_LIMITED_API
+#if 0
     return _Py_Mangle(privateobj, name);
 #else
     // PYSIDE-1436: _Py_Mangle is no longer exposed; implement it always.