Since Python 3.7.0, calling :c:func:`Py_DecodeLocale` before :c:func:`Py_Initialize` produces mojibake if the LC_CTYPE locale is coerced and/or if the UTF-8 Mode is enabled by the user configuration. The LC_CTYPE coercion and UTF-8 Mode are now disabled by default to fix the mojibake issue. They must now be enabled explicitly (opt-in) using the new :c:func:`_Py_PreInitialize` API with _PyPreConfig.