Python.org provides two installer variants for download: one that installs a

\i0 or later; and one that installs a

\i0 Python capable of running on

\i0 or later. This ReadMe was installed with the

\i0 variant. Unless you are installing to an 10.5 system or you need to build applications that can run on 10.5 systems, use the 10.6 variant if possible. There are some additional operating system functions that are supported starting with 10.6 and you may see better performance using 64-bit mode. By default, Python will automatically run in 64-bit mode if your system supports it. Also see

\i0 below. The Pythons installed by these installers are built with private copies of some third-party libraries not included with or newer than those in OS X itself. The list of these libraries varies by installer variant and is included at the end of the License.rtf file.

\i0 for this version of Python and of Mac OS X.\

Python 3.5 includes a number of network security enhancements that were released in Python 3.4.3 and Python 2.7.10. {\field{\*\fldinst{HYPERLINK "https://www.python.org/dev/peps/pep-0476/"}}{\fldrslt PEP 476}} changes several standard library modules, like

For OS X 10.5, Apple provides

\i0 libraries. This version of Apple's OpenSSL

\b0 use the certificates from the system security framework, even when used on newer versions of OS X. Instead it consults a traditional OpenSSL concatenated certificate file (

\i0 ) or certificate directory (

\i0 ), located in

\f1 /System/Library/OpenSSL

\f0 . These directories are typically empty and not managed by OS X; you must manage them yourself or supply your own SSL contexts. OpenSSL 0.9.7 is obsolete by current security standards, lacking a number of important features found in later versions. Among the problems this causes is the inability to verify higher-security certificates now used by python.org services, including

\i0 . To solve this problem, the

\i0 is linked with a private copy of

\i0 ; it consults the same default certificate directory,

\f1 /System/Library/OpenSSL

\f0 . As before, it is still necessary to manage certificates yourself when you use this Python variant and, with certificate verification now enabled by default, you may now need to take additional steps to ensure your Python programs have access to CA certificates you trust. If you use this Python variant to build standalone applications with third-party tools like {\field{\*\fldinst{HYPERLINK "https://pypi.python.org/pypi/py2app/"}}{\fldrslt

\f1 py2app}}, you may now need to bundle CA certificates in them or otherwise supply non-default SSL contexts.\

\f0 , the certificates managed by the system security framework In the user and system keychains are also consulted (using Apple private APIs). For this reason, the

\i0 continues to be dynamically linked with Apple's OpenSSL 0.9.8 since it was felt that the loss of the system-provided certificates and management tools outweighs the additional security features provided by newer versions of OpenSSL. This will likely change in future releases of the python.org installers as Apple has deprecated use of the system-supplied OpenSSL libraries. If you do need features from newer versions of OpenSSL, there are third-party OpenSSL wrapper packages available through

\f0 included with the Python 3.5 installers has its own default certificate store for verifying download connections.\

\cf0 For other changes in this release, see the