The latest Python version is 3.7 (2018-08-31). Still wants to know what version do they use and if any possible will they update its course to latest version?
The old course is Python 2.7.x. As new iterations surface it looks like they are making the switch to 3.x. It will not be happening in the free tracks.
As @mtf said, the Python course is mainly based on Python 2.
There are some differences between Python 2 and Python 3, which you can easily discover from reading the Python docs, but this does not mean there’s no value in completing the course based on Python 2. 