PyCharm Python Version Downgrade Guide: How to Safely Downgrade Python Versions

# Guide to Downgrading Python Version in PyCharm: How to Safely Downgrade Python Versions ## 1. Necessity of Downgrading Python Versions Downgrading the Python version is necessary in certain situations, for example: - **Dependency Library Compatibility Issues:** Newer versions of Python may not be compatible with certain dependency libraries, causing the program to malfunction. Downgrading to a compatible Python version can solve this issue. - **Project Code Compatibility Issues:** Newer versions of Python may introduce syntactic or semantic changes, causing old code to not run. Downgrading to a compatible Python version can ensure the normal operation of the code. - **Environment Variable Adjustments:** Different versions of Python may require different environment variable settings. Downgrading to a lower version of Python can avoid environment variable conflicts and ensure the normal operation of the program. ## 2. Steps for Downgrading Python Versions ### 2.1 Backup Current Environment Before beginning the downgrade, it is highly recommended to back up the current Python environment. This will ensure that you can easily revert to the original state in case of any problems. **Steps:** 1. Open the command prompt or terminal window. 2. Navigate to the Python environment directory to be backed up. 3. Run the following command: ``` pip freeze > requirements.txt ``` This command will create a file named `requirements.txt`, which contains all packages and their versions currently installed in the environment. ### 2.2 Uninstall Current Python Version Uninstalling the current Python version is crucial to free up space for the target version. **Steps:** 1. Open the command prompt or terminal window. 2. Run the following command: ``` python -m pip uninstall --user python ``` This command will uninstall the user-installed Python version. ### 2.3 Install Target Python Version Now you can install the target Python version. **Steps:** 1. Download the target Python version from the official Python website. 2. Run the installer and follow the prompts. 3. Verify successful installation by running: ``` python --version ``` ### 2.4 Restore Environment Variables After the downgrade, it is necessary to update the environment variables to point to the newly installed Python version. **Steps:** 1. Open the command prompt or terminal window. 2. Run the following command: ``` setx PATH "%PATH%;C:\Python39" ``` Please note that this path should be replaced with the actual path of the newly installed Python version. ### 2.5 Verify Downgrade Success Finally, verify that the Python version has been successfully downgraded. **Steps:** 1. Open the command prompt or terminal window. 2. Run the following command: ``` python --version ``` This co