Release Date: June 6, 2023

This is the fourth maintenance release of Python 3.11

Python 3.11.4 is the newest major release of the Python programming language, and it contains many new features and optimizations.

Major new features of the 3.11 series, compared to 3.10

Some of the new major new features and changes in Python 3.11 are:

General changes

• PEP 657 -- Include Fine-Grained Error Locations in Tracebacks
• PEP 654 -- Exception Groups and except*
• PEP 680 -- tomllib: Support for Parsing TOML in the Standard Library
• gh-90908 -- Introduce task groups to asyncio
• gh-34627 -- Atomic grouping ((?>...)) and possessive quantifiers (*+, ++, ?+, {m,n}+) are now supported in regular expressions.
• The Faster CPython Project is already yielding some exciting results. Python 3.11 is up to 10-60% faster than Python 3.10. On average, we measured a 1.22x speedup on the standard benchmark suite. See Faster CPython for details.

Typing and typing language changes

• PEP 673 -- Self Type
• PEP 646 -- Variadic Generics
• PEP 675 -- Arbitrary Literal String Type
• PEP 655 -- Marking individual TypedDict items as required or potentially-missing
• PEP 681 -- Data Class Transforms

More resources

• Online Documentation
• PEP 664, 3.11 Release Schedule
• Report bugs at https://github.com/python/cpython/issues.
• Help fund Python and its community.

And now for something completely different

The non-squeezing theorem, also called Gromov's non-squeezing theorem, is one of the most important theorems in symplectic geometry. It was first proven in 1985 by Mikhail Gromov. The theorem states that one cannot embed a ball into a cylinder via a symplectic map unless the radius of the ball is less than or equal to the radius of the cylinder. The theorem is important because formerly very little was known about the geometry behind symplectic maps.

One easy consequence of a transformation being symplectic is that it preserves volume. One can easily embed a ball of any radius into a cylinder of any other radius by a volume-preserving transformation: just picture squeezing the ball into the cylinder (hence, the name non-squeezing theorem). Thus, the non-squeezing theorem tells us that, although symplectic transformations are volume-preserving, it is much more restrictive for a transformation to be symplectic than it is to be volume-preserving.

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