Should I use Python 2 or Python 3 for my development activity?
You should use Python 3. Since January 2020 Python 2 reached the EOL (End Of Life) status, meaning it receives no further updates nor bugfixes. As such, we can only recommend learning and teaching Python 3.
Historical information
For historical information that may be useful in porting or maintaining remaining Python 2 systems, please see previous page revisions.