The first thing to ask is this: what exactly changed in Python 3? And, how easily can you move from Python 2 to Python 3? Or, how can you modify your Python 2 programs so they'll continue to work in Python 2, but then also work unmodified in Python 3? This last question is probably the most important one for my clients, and possibly for your business as well, during this transition period.
On the face of things, not very much actually changed in Python 3. It's a cleaner, more efficient and modern language that works like more modern Python developers want and expect. Things that Python developers were doing for years, but that weren't defaults in the language, are now indeed defaults. Sure, there are things I'm still getting used to after years of bad habits, such as failing to use parentheses around the arguments passed to print, but on the whole, the language has stayed the same.
However, this doesn't mean that nothing has changed or that you can get away with not changing your code.
thanks for question.