If you are just starting out with Django, you might be overwhelmed with the fast pace of Django’s release cycle. About every eight months, a new feature release becomes available (1.8, 1.9, 1.10 etc.). In addition to that, there is a new patch release every few weeks (1.9.6, 1.9.7, 1.9.8 etc).
This means Django is continuously advancing and becoming more secure, stable and powerful, but it also makes it really hard for third-party documentation to keep up with the latest version. As I wrote in my post comparing different free Django tutorials, as of September 2016, all third-party tutorials refer to Django 1.8 while the current version of Django is 1.10. This is not as bad as it sounds, because Django 1.8 is a long-term support (LTS) release and will therefor receive security and data loss fixes until about April 2018.
As a rule of thumb, I would say, try to learn the newest version of Django, but at least a version that is still supported. Currently, that means Django 1.8 or newer. Don’t waste your time – and your money, if you are planning to buy a video course or a physical book on Django – on anything that still refers to Django 1.7 or older.
Just like any good rule, this one has its exceptions: if you are learning Django to take over maintenance of a legacy application, it might be a good idea to learn the version of Django your application was written for. However, if this application is running on an unsupported version of Django, one of first tasks should probably be to update to a supported version or backport the security fixes from newer versions.
One last tip: No matter what Django version you decide to use, make sure that your learning material matches the version of Django you are using.