How to change django version in PyCharm?

In default settings of project.

File -> Default Settings -> Default Project -> Project Interpretatoe

You don't do that with Pycharm, Pycharm just detects the installed version. You change the version with pip:

pip uninstall django # just for explicity
pip install django==1.6.8

Make sure you use virtual environments if you run multiple applications on the same machine.

Go to Settings->Project Interpreter.

Double-click the Django package. Activate the check box Specify version and select the version you want.

Press the button Install Package.

Django will use pip in the background to install the package.