如何降级至Python 2.7.13（2017-11-07默认版）及兼容问题解决

Let's tackle this step by step—first getting the specific Python version your project needs, then sorting out that Flask module warning.

1. Installing the Exact Python 2.7.13 (Nov 7, 2017) #

Python 2.7.13 had two distinct builds: the initial release on November 7, 2017, and a maintenance update on March 6, 2018. To get the exact build your project requires, follow these OS-specific steps:

For Linux/macOS #

• Download and verify the correct source package:
  Locate the initial 2017 release of Python 2.7.13 in the official Python download archives. Grab the Python-2.7.13.tgz source tarball, then verify its SHA256 hash matches 828b3096e142b9a4ba64699c30f40b8e4c934e078f5a052bc6c522c3e244d990 to ensure you have the right version. Check the hash using:

  sha256sum Python-2.7.13.tgz
  

• Compile and install to an isolated directory:
  Avoid overwriting your system's default Python by installing this version to a dedicated path:

  tar xzf Python-2.7.13.tgz
  cd Python-2.7.13
  # Configure the installation path (adjust /usr/local/python2713 to your preferred location)
  ./configure --prefix=/usr/local/python2713 --enable-optimizations
  make
  sudo make install
  

• Create a virtual environment for your project:
  Use a virtual environment to ensure your project uses only this specific Python version:

  # Install virtualenv with the new Python
  /usr/local/python2713/bin/pip install virtualenv
  # Create a virtual environment tied to this Python
  /usr/local/python2713/bin/virtualenv -p /usr/local/python2713/bin/python my_project_env
  # Activate it
  source my_project_env/bin/activate
  

  Once activated, running python --version should show the 2017-11-07 build.

For Windows #

• Download and verify the installer:
  Find the Windows installers for the 2017-11-07 release of Python 2.7.13. The 32-bit installer has a SHA256 hash of a96c65c0d349bb955595a440b70f373504373d5b87e392a3384064901260e5f6, and the 64-bit version's hash is f8f103079e1a6900e69e7e91be1e5e33e84f80d8f464a4c60b71301059f8c2d4. Download the correct installer and verify its hash to confirm it's the right build.
• Install to a unique path:
  Run the installer, select Custom Installation, and choose a dedicated directory (like C:\Python2713) to prevent overwriting other Python versions on your system.
• Set up a virtual environment:
  Use virtualenv (install it via the new Python installation) to create an isolated environment for your project, pointing to the python.exe in C:\Python2713.

2. Fixing the Flask Deprecation Warning #

That warning isn't related to your Python version—it's a change in how Flask-SQLAlchemy is imported. The old flask.ext.* syntax was deprecated in favor of direct package imports. To fix it, update your code:

# Replace this deprecated line
from flask.ext.sqlalchemy import SQLAlchemy

# With this official recommended syntax
from flask_sqlalchemy import SQLAlchemy

This change is fully compatible with Python 2.7.13 and will eliminate the warning.

内容的提问来源于stack exchange，提问作者Houy Narun