PEP 11: Clarify Fixed vs. Modern lifecycle & non-support of ESU (#2802)

* PEP 11: Elide long-obselete emacs declaration & header fields
* PEP 11: Convert last footnote to inline link, fix redirect & use HTTPS
* PEP 11: Apply ESU textual fixes/improvements suggested on #2801
* PEP 11: Update Windows section to clarify Fixed vs. Modern lifecycle
* PEP 11: Apply reviewer-suggested tweaks

Co-authored-by: Steve Dower <steve.dower@microsoft.com>

pep-0011.txt

@@ -1,7 +1,5 @@
 PEP: 11
 Title: CPython platform support
-Version: $Revision$
-Last-Modified: $Date$
 Author: Martin von Löwis <martin@v.loewis.de>,
         Brett Cannon <brett@python.org>
 Status: Active
@@ -154,19 +152,37 @@ Notes
 Microsoft Windows
 '''''''''''''''''
 
-Microsoft has established a policy called product support lifecycle
+Windows versions prior to Windows 10 follow Microsoft's `Fixed Lifecycle Policy
-[1]_. Each product's lifecycle has a mainstream support phase, where
+<https://learn.microsoft.com/en-us/lifecycle/policies/fixed>`__,
-the product is generally commercially available, and an extended
+with a mainstream support phase for 5 years after release,
-support phase, where paid support is still available, and certain bug
+where the product is generally commercially available,
-fixes are released. Sometimes this is then followed by a third phase
+and an additional 5 year extended support phase,
-called "ESU", for "extended security updates".
+where paid support is still available and certain bug fixes are released.
+`Extended Security Updates (ESU)
+<https://learn.microsoft.com/en-us/lifecycle/faq/extended-security-updates>`_
+is a paid program available to high-volume enterprise customers
+as a "last resort" option to receive certain security updates after extended support ends.
+ESU is considered a distinct phase that follows the expiration of extended support.
 
-CPython's Windows support now follows this lifecycle. A new feature
+Windows 10 and later follow Microsoft's `Modern Lifecycle Policy
-release X.Y.0 will support all Windows releases whose extended support
+<https://learn.microsoft.com/en-us/lifecycle/policies/modern>`__,
-phase is not yet expired. (We don't consider the ESU phase for this
+which varies per-product, per-version, per-edition and per-channel.
-purpose; only the "extended support" phase.) Subsequent bug fix releases
+Generally, feature updates (1709, 22H2) occur every 6-12 months
-will support the same Windows releases as the original feature release
+and are supported for 18-36 months;
-(even if the extended support phase has ended).
+Server and IoT editions, and LTSC channel releases are supported for 5-10 years,
+and the latest feature release of a major version (Windows 10, Windows 11)
+generally receives new updates for at least 10 years following release.
+Microsoft's `Windows Lifecycle FAQ
+<https://learn.microsoft.com/en-us/lifecycle/faq/windows>`_
+has more specific and up-to-date guidance.
+
+CPython's Windows support currently follows Microsoft's lifecycles.
+A new feature release X.Y.0 will support all Windows versions
+whose *extended support* phase has not yet expired.
+Subsequent bug fix releases will support the same Windows versions
+as the original feature release, even if no longer supported by Microsoft.
+New versions of Windows released while CPython is in maintenance mode
+may be supported at the discretion of the core team and release manager.
 
 Each feature release is built by a specific version of Microsoft
 Visual Studio. That version should have mainstream support when the
@@ -360,24 +376,8 @@ Discussions
   (Skip Montanaro)
 
 
-References
-==========
-
-.. [1] http://support.microsoft.com/lifecycle/
-
 Copyright
 =========
 
 This document is placed in the public domain or under the
 CC0-1.0-Universal license, whichever is more permissive.
-
-
-
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