Warning
Python bugfix releases 2.6.8, 2.7.3, 3.1.5 and 3.2.3 include a change that will cause “import random” to fail with “cannot import name urandom” on any virtualenv created on a Unix host with an earlier release of Python 2.6/2.7/3.1/3.2, if the underlying system Python is upgraded. This is due to the fact that a virtualenv uses the system Python’s standard library but contains its own copy of the Python interpreter, so an upgrade to the system Python results in a mismatch between the version of the Python interpreter and the version of the standard library. It can be fixed by removing $ENV/bin/python and re-running virtualenv on the same target directory with the upgraded Python.
BACKWARDS INCOMPATIBLE Dropped support for Python 2.5. The minimum supported Python version is now Python 2.6.
BACKWARDS INCOMPATIBLE Using virtualenv.py as an isolated script (i.e. without an associated virtualenv_support directory) is no longer supported for security reasons and will fail with an error.
Along with this, --never-download is now always pinned to True, and is only being maintained in the short term for backward compatibility (Pull #412).
IMPORTANT Switched to the new setuptools (v0.9.7) which has been merged with Distribute again and works for Python 2 and 3 with one codebase. The --distribute and --setuptools options are now no-op.
Updated to pip 1.4.
Added support for PyPy3k
Added the option to use a version number with the -p option to get the system copy of that Python version (Windows only)
Removed embedded ez_setup.py, distribute_setup.py and distribute_from_egg.py files as part of switching to merged setuptools.
Fixed --relocatable to work better on Windows.
Fixed issue with readline on Windows.
Fixed packaging of the library.
Initial release. Everything is changed and new!