All of the code samples in this book have been written for Python 3.6. Except for very minor changes, they should work in Python 2.7 as well. The author believes that Python 3 has crossed the tipping point for being the preferred choice for new Django projects.
Python 2.7 development was supposed to end in 2015 but was extended for 5 more years, through to 2020. There will not be a Python 2.8. As mentioned in Chapter 2, Application Design, most major Linux distributions and cloud vendors have completely switched to using Python 3 as a default or support it.
This appendix has been written for developers who are not familiar with Python 3. A brief historical background and syntax changes in Python 3 are discussed. Rather than offering exhaustive coverage of Python 3 features, only the relevant ones for Django developers are covered.