I’m teaching a class next week, and in their work environment, the students are limited to using Python 2.4. I wanted to be clear about what features of Python they’d have available, and which they wouldn’t. The “What’s New in Python” docs are very comprehensive, but spread out across many pages and full of distracting details.

So I made this list of the high points, what’s in each version of Python 2.x. Items with a star were introduced with a __future__ import.

Update: I’ve now collected all the “What’s in which Python”s onto a single page: What’s in which Python.

BTW: there’s also What’s in which Python 3.0–3.3? and What’s in which Python 3.4–3.6?.

2.1: April 17th, 2001

• Nested scopes *
• “from __future__”
• Rich comparisons
• Weak references

Full list of 2.1 changes.

2.2: December 21st, 2001

• New-style classes
• Iterators
• Generators *
• // integer division
• Dividing ints can produce floats *

Full list of 2.2 changes.

2.3: July 29th, 2003

• Set datatype module
• Boolean datatype
• Importing from zip files
• enumerate
• The logging and csv packages
• Extended list slicing

Full list of 2.3 changes.

2.4: November 30th, 2004

• Native set datatype
• Generator expressions
• Function decorators
• string.Template
• reversed()
• The subprocess and decimal modules

Full list of 2.4 changes.

2.5: September 19th, 2006

• The “with” statement *
• Conditional expressions
• The functools module
• Unified try/except/finally
• Value passed into generators
• defaultdict
• any(), all(), min(key=) and max(key=)

Full list of 2.5 changes.

2.6: October 1st, 2008

• The multiprocessing package
• str.format()
• 3.0 compatibility: print function *, byte literals, io library
• “except” with “as” keyword
• Abstract base classes
• Class decorators
• The fractions module

Full list of 2.6 changes.

2.7: July 3rd, 2010

• Set literals syntax
• Dictionary and set comprehensions
• OrderedDict and Counter classes
• argparse
• .format can use bare {} placeholders

Full list of 2.7 changes.