Python3 When to use? What libraries are available?

Question

I am going to develop new applications in python3.

Application Requirements:

File IO, JSON, DB, Well support for Unicode, Web (optional). Desktop GUI (optional), indexing, and TCP / IP.

so here are the questions:

• Do you think we will use python 3 for realworld applications? The site said that "it will not use python3 for many years," "it was three years ago."
• Of the above needs that are available for open source libraries for python 3?
• Is it true that Python2 is still superior to python3 in the I / O area?