Checkout the issues that you may also encounter while upgrading your Django application and Python interpreter. I have posted here the actual error messages and how to fix the errors. Also how to setup a test environment and upgrade the SQLite3 version requirement from source.
The behavior of Pass by Reference could get tricky sometimes. It can cause Logical error where your code return unexpected result if you do not know how to deal with this. Imagine if your Client gets a duplicate item in their shopping cart and the charge on their account got doubled, that could be a problem!