This package will install Python $FULL_VERSION for macOS $MACOSX_DEPLOYMENT_TARGET for the following architecture(s): $ARCHITECTURES.

Certificate verification and OpenSSL

This package includes its own private copy of OpenSSL 3.0.   The trust certificates in system and user keychains managed by the Keychain Access application and the security command line utility are not used as defaults by the Python ssl module.  A sample command script is included in /Applications/Python 3.12 to install a curated bundle of default root certificates from the third-party certifi package (https://pypi.org/project/certifi/).  Double-click on Install Certificates to run it.

The bundled pip has its own default certificate store for verifying download connections.

(Updated for 3.12.5): If you are using this installer on older, legacy versions of macOS, specifically macOS 10.9 through 10.12, the bundled version of pip (pip 24.2) included with this installer does not work correctly on these old versions of macOS.  pip install commands may fail with a message similar to SecTrustEvaluateWithError: symbol not found. (see https://github.com/pypa/pip/issues/12901 for more information). To work around this issue, the Install Certificates command (described above) has been modified when running on these older macOS releases to attempt to first install an older version of pip that does not have this problem. You should avoid upgrading pip on these older systems until this problem has been resolved in a newer release of pip. If necessary, you can rerun Install Certificates at any time to attempt to revert to a working version of pip.

Install Options

You can control some aspects of what is installed by this package. To see the options, click on the Customize button in the Installation Type step of the macOS installer app.  Click on a package name in the list shown to see more information about that option,
  
Using IDLE or other Tk applications 

This package includes its own private version of Tcl/Tk 8.6. It does not use any system-supplied or third-party supplied versions of Tcl/Tk.

Due to new security checks on macOS 10.15 Catalina, when launching IDLE macOS may open a window with a message "Python" would like to access files in your Documents folder.  This is normal as IDLE uses your Documents folder as its default when opening and saving files; you can still choose other locations in the Open and Save file dialog windows.  Click on the OK button to proceed.

Apple Silicon Mac support

On Apple Silicon Macs, it is possible to run Python either with native ARM64 code or under Intel 64 emulation using Rosetta2. This option might be useful for testing or if binary wheels are not yet available with native ARM64 binaries.  To  easily force Python to run in emulation mode, invoke it from a command line shell with the python3-intel64 command instead of just python3.

Installer support for macOS 10.9 through 10.12 to be discontinued

(Updated for 3.12.5): Up to now, python.org macOS installers have supported installation and running of Python 3.12.x on macOS releases as old as 10.9 Mavericks (which was first released in 2013). However, over time, it has become more difficult to continue supporting these older macOS releases. These operating system releases have long stopped receiving security updates and the most recent versions of Apple's Xcode developer tools no longer support building for these older systems, making it difficult for third-party developers to build and test their packages for them. We believe that only a very small and dwindling number of users are using these installers on these older macOS systems and thus believe that we can better serve the entire community by dropping support of these older macOS versions in future releases of Python 3.12.x installers. We have already announced that macOS installers for the next feature release of Python, 3.13, will initially support macOS 10.13 and newer releases. If you have a continued need for running Python 3.12 on these older systems, pre-built versions for these systems may be available from third-party distributors (such as MacPorts) or Python can be built from source (https://www.python.org/downloads/source/).

Other changes

For other changes in this release, see the What's new section in the Documentation Set for this release and its Release Notes link at https://www.python.org/downloads/.