• Anew and improved interactive interpreter, based onPyPy's, featuring multi-line editing and color support, as well as colorizedexception tracebacks.
• Anexperimental free-threaded build mode, which disables the Global Interpreter Lock, allowing threads to run more concurrently. The build mode is available as an experimental feature in the Windows and macOS installers as well.
• Apreliminary,experimental JIT, providing the ground work for significant performance improvements.
• Thelocals() builtin function (and its C equivalent) now haswell-defined semantics when mutating the returned mapping, which allows debuggers to operate more consistently.
• A modified version ofmimalloc is now included, optional but enabled by default if supported by the platform, and required for the free-threaded build mode.
• Docstrings now havetheir leading indentation stripped, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• Thedbm module has a newdbm.sqlite3 backend that is used by default when creating new files.
• The minimum supported macOS version was changed from 10.9 to10.13 (High Sierra). Older macOS versions will not be supported going forward.
• WASI is now aTier 2 supported platform. Emscripten is no longer anofficially supported platform (butPyodide continues to support Emscripten).
• iOS is now aTier 3 supported platform.
• Android is now aTier 3 supported platform.

Typing

• Support fortype defaults in type parameters.
• Anew type narrowing annotation,typing.TypeIs.
• A new annotation forread-only items in TypeDicts.
• A new annotation formarking deprecations in the type system.

Removals and new deprecations

• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules:aifc,audioop,chunk,cgi,cgitb,crypt,imghdr,mailcap,msilib,nis,nntplib,ossaudiodev,pipes,sndhdr,spwd,sunau,telnetlib,uu,xdrlib,lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• C APIremovals anddeprecations. (Some removals present in alpha 1 were reverted in alpha 2, as the removals were deemed too disruptive at this time.)
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.

For more details on the changes to Python 3.13, seeWhat's new in Python 3.13.

More resources

• Online Documentation
• PEP 719, 3.13 Release Schedule
• Report bugs athttps://github.com/python/cpython/issues.
• Help fund Python directly (orvia GitHub Sponsors), and supportthe Python community.

Full Changelog