pyenv does not upgrade anything

gistfile1.irclog

foxmask@foxmask:~/.pyenv/versions/django-th-340$ pyenv virtualenv django-th-340  --help
Usage: pyenv virtualenv [-f|--force] [-u|--upgrade] [VIRTUALENV_OPTIONS] <version> <virtualenv-name>
       pyenv virtualenv --version
       pyenv virtualenv --help

  -u/--upgrade     Upgrade existing virtualenv to use new version of Python,
                   assuming Python has been upgraded in-place.
  -f/--force       Install even if the version appears to be installed already

foxmask@foxmask:~/.pyenv/versions/django-th-340$ python --version
Python 3.4.2
foxmask@foxmask:~/.pyenv/versions/django-th-340$ pyenv virtualenv django-th-340  --upgrade
pyenv-virtualenv: /home/foxmask/.pyenv/versions/django-th-340 already exists
continue with installation? (y/N) Y
Ignoring indexes: https://pypi.python.org/simple/
Requirement already satisfied (use --upgrade to upgrade): setuptools in /home/foxmask/.pyenv/versions/django-th-340/lib/python3.4/site-packages
Requirement already satisfied (use --upgrade to upgrade): pip in /home/foxmask/.pyenv/versions/django-th-340/lib/python3.4/site-packages
Cleaning up...
foxmask@foxmask:~/.pyenv/versions/django-th-340$ python --version
Python 3.4.2
foxmask@foxmask:~/.pyenv/versions/django-th-340$ source bin/activate
(django-th-340) foxmask@foxmask:~/.pyenv/versions/django-th-340$ python --version
Python 3.4.0
(django-th-340) foxmask@foxmask:~/.pyenv/versions/django-th-340$ deactivate
foxmask@foxmask:~/.pyenv/versions/django-th-340$ python --version
Python 3.4.2
foxmask@foxmask:~/.pyenv/versions/django-th-340$ pyenv virtualenv django-th-340  --upgrade -f
Ignoring indexes: https://pypi.python.org/simple/
Requirement already satisfied (use --upgrade to upgrade): setuptools in /home/foxmask/.pyenv/versions/django-th-340/lib/python3.4/site-packages
Requirement already satisfied (use --upgrade to upgrade): pip in /home/foxmask/.pyenv/versions/django-th-340/lib/python3.4/site-packages
Cleaning up...
foxmask@foxmask:~/.pyenv/versions/django-th-340$ python --version
Python 3.4.2
foxmask@foxmask:~/.pyenv/versions/django-th-340$ source bin/activate
(django-th-340) foxmask@foxmask:~/.pyenv/versions/django-th-340$ python --version
Python 3.4.0
(django-th-340) foxmask@foxmask:~/.pyenv/versions/django-th-340$ pyenv virtualenv --version
pyenv-virtualenv 20140123 (pyvenv 3.4.2)