Major new features of the 3.3 series, compared to 3.2

Python 3.3 includes a range of improvements of the 3.x series, as well as easier porting between 2.x and 3.x.

• PEP 380, syntax for delegating to a subgenerator (yield from)
• PEP 393, flexible string representation (doing away with the distinction between "wide" and "narrow" Unicode builds)
• A C implementation of the "decimal" module, with up to 120x speedup for decimal-heavy applications
• The import system (__import__) is based on importlib by default
• The new "lzma" module with LZMA/XZ support
• PEP 397, a Python launcher for Windows
• PEP 405, virtual environment support in core
• PEP 420, namespace package support
• PEP 3151, reworking the OS and IO exception hierarchy
• PEP 3155, qualified name for classes and functions
• PEP 409, suppressing exception context
• PEP 414, explicit Unicode literals to help with porting
• PEP 418, extended platform-independent clocks in the "time" module
• PEP 412, a new key-sharing dictionary implementation that significantly saves memory for object-oriented code
• PEP 362, the function-signature object
• The new "faulthandler" module that helps diagnosing crashes
• The new "unittest.mock" module
• The new "ipaddress" module
• The "sys.implementation" attribute
• A policy framework for the email package, with a provisional (see PEP 411) policy that adds much improved unicode support for email header parsing
• A "collections.ChainMap" class for linking mappings to a single unit
• Wrappers for many more POSIX functions in the "os" and "signal" modules, as well as other useful functions such as "sendfile()"
• Hash randomization, introduced in earlier bugfix releases, is now switched on by default

More resources

• Change log for this release.
• Online Documentation
• What's new in 3.3?
• 3.3 Release Schedule
• Report bugs at http://bugs.python.org.
• Help fund Python and its community.

This is a preview release, and its use is not recommended in production settings.