After two years of experimental status, --disable-gil builds are now on Linux, macOS, and Windows. Performance overhead reduced by 40% compared to 3.13.0. Use sys.set_thread_limit() to avoid resource exhaustion.
| Feature | Status | |---------|--------| | | Confirmed fully removed in 3.13.0; 3.13.1 includes a small shim that raises a clear ImportError with migration guidance. | | collections.abc.MutableMapping | Deprecation warning removed (the class is now fully stable). | | asyncio.get_event_loop() | The DeprecationWarning now escalates to an ImportWarning when called from a non‑main thread, encouraging use of asyncio.get_running_loop() . | python 3.13.1 release notes november 2025