Create new perldelta for 5.20.4

10 files changed, 568 insertions, 146 deletions

diff --git a/MANIFEST b/MANIFEST
index af12626c21..da8a493c63 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -4603,6 +4603,7 @@ pod/perl5184delta.pod		Perl changes in version 5.18.4
 pod/perl5200delta.pod		Perl changes in version 5.20.0
 pod/perl5201delta.pod		Perl changes in version 5.20.1
 pod/perl5202delta.pod		Perl changes in version 5.20.2
+pod/perl5203delta.pod		Perl changes in version 5.20.3
 pod/perl561delta.pod		Perl changes in version 5.6.1
 pod/perl56delta.pod		Perl changes in version 5.6
 pod/perl581delta.pod		Perl changes in version 5.8.1
diff --git a/Makefile.SH b/Makefile.SH
index ee2517dbc5..a9773180fc 100755
--- a/Makefile.SH
+++ b/Makefile.SH
@@ -491,7 +491,7 @@ mini_obj = $(minindt_obj) $(MINIDTRACE_O)
 ndt_obj = $(obj0) $(obj1) $(obj2) $(obj3) $(ARCHOBJS)
 obj = $(ndt_obj) $(DTRACE_O)
 
-perltoc_pod_prereqs = extra.pods pod/perl5203delta.pod pod/perlapi.pod pod/perlintern.pod pod/perlmodlib.pod pod/perluniprops.pod
+perltoc_pod_prereqs = extra.pods pod/perl5204delta.pod pod/perlapi.pod pod/perlintern.pod pod/perlmodlib.pod pod/perluniprops.pod
 generated_pods = pod/perltoc.pod $(perltoc_pod_prereqs)
 generated_headers = uudmap.h bitcount.h mg_data.h
 
@@ -1016,9 +1016,9 @@ pod/perlintern.pod: $(MINIPERL_EXE) autodoc.pl embed.fnc
 pod/perlmodlib.pod: $(MINIPERL_EXE) pod/perlmodlib.PL MANIFEST
 	$(MINIPERL) pod/perlmodlib.PL -q
 
-pod/perl5203delta.pod: pod/perldelta.pod
-	$(RMS) pod/perl5203delta.pod
-	$(LNS) perldelta.pod pod/perl5203delta.pod
+pod/perl5204delta.pod: pod/perldelta.pod
+	$(RMS) pod/perl5204delta.pod
+	$(LNS) perldelta.pod pod/perl5204delta.pod
 
 extra.pods: $(MINIPERL_EXE)
 	-@test ! -f extra.pods || rm -f `cat extra.pods`
diff --git a/pod/.gitignore b/pod/.gitignore
index 3e14c5ba8d..1c754127b5 100644
--- a/pod/.gitignore
+++ b/pod/.gitignore
@@ -59,7 +59,7 @@
 /roffitall
 
 # generated
-/perl5203delta.pod
+/perl5204delta.pod
 /perlapi.pod
 /perlintern.pod
 *.html
diff --git a/pod/perl.pod b/pod/perl.pod
index 5155344812..9cdaf61ca8 100644
--- a/pod/perl.pod
+++ b/pod/perl.pod
@@ -180,6 +180,7 @@ aux a2p c2ph h2ph h2xs perlbug pl2pm pod2html pod2man s2p splain xsubpp
 
     perlhist		Perl history records
     perldelta		Perl changes since previous version
+    perl5203delta	Perl changes in version 5.20.3
     perl5202delta	Perl changes in version 5.20.2
     perl5201delta	Perl changes in version 5.20.1
     perl5200delta	Perl changes in version 5.20.0
diff --git a/pod/perl5203delta.pod b/pod/perl5203delta.pod
new file mode 100644
index 0000000000..7c22b7b6f0
--- /dev/null
+++ b/pod/perl5203delta.pod
@@ -0,0 +1,312 @@
+=encoding utf8
+
+=head1 NAME
+
+perl5203delta - what is new for perl v5.20.3
+
+=head1 DESCRIPTION
+
+This document describes differences between the 5.20.2 release and the 5.20.3
+release.
+
+If you are upgrading from an earlier release such as 5.20.1, first read
+L<perl5202delta>, which describes differences between 5.20.1 and 5.20.2.
+
+=head1 Incompatible Changes
+
+There are no changes intentionally incompatible with 5.20.2.  If any exist,
+they are bugs, and we request that you submit a report.  See L</Reporting Bugs>
+below.
+
+=head1 Modules and Pragmata
+
+=head2 Updated Modules and Pragmata
+
+=over 4
+
+=item *
+
+L<Errno> has been upgraded from version 1.20_05 to 1.20_06.
+
+Add B<-P> to the pre-processor command-line on GCC 5.  GCC added extra line
+directives, breaking parsing of error code definitions.
+L<[perl #123784]|https://rt.perl.org/Ticket/Display.html?id=123784>
+
+=item *
+
+L<Module::CoreList> has been upgraded from version 5.20150214 to 5.20150822.
+
+Updated to cover the latest releases of Perl.
+
+=item *
+
+L<perl5db.pl> has been upgraded from 1.44 to 1.44_01.
+
+The debugger would cause an assertion failure.
+L<[perl #124127]|https://rt.perl.org/Ticket/Display.html?id=124127>
+
+=back
+
+=head1 Documentation
+
+=head2 Changes to Existing Documentation
+
+=head3 L<perlfunc>
+
+=over 4
+
+=item *
+
+Mention that L<C<study()>|perlfunc/study> is currently a no-op.
+
+=back
+
+=head3 L<perlguts>
+
+=over 4
+
+=item *
+
+The OOK example has been updated to account for COW changes and a change in the
+storage of the offset.
+
+=back
+
+=head3 L<perlhacktips>
+
+=over 4
+
+=item *
+
+Documentation has been added illustrating the perils of assuming the contents
+of static memory pointed to by the return values of Perl wrappers for C library
+functions doesn't change.
+
+=back
+
+=head3 L<perlpodspec>
+
+=over 4
+
+=item *
+
+The specification of the POD language is changing so that the default encoding
+of PODs that aren't in UTF-8 (unless otherwise indicated) is CP1252 instead of
+ISO-8859-1 (Latin1).
+
+=back
+
+=head1 Utility Changes
+
+=head2 L<h2ph>
+
+=over 4
+
+=item *
+
+B<h2ph> now handles hexadecimal constants in the compiler's predefined macro
+definitions, as visible in C<$Config{cppsymbols}>.
+L<[perl #123784]|https://rt.perl.org/Ticket/Display.html?id=123784>
+
+=back
+
+=head1 Testing
+
+=over 4
+
+=item *
+
+F<t/perf/taint.t> has been added to see if optimisations with taint issues are
+keeping things fast.
+
+=item *
+
+F<t/porting/re_context.t> has been added to test that L<utf8> and its
+dependencies only use the subset of the C<$1..$n> capture vars that
+Perl_save_re_context() is hard-coded to localize, because that function has no
+efficient way of determining at runtime what vars to localize.
+
+=back
+
+=head1 Platform Support
+
+=head2 Platform-Specific Notes
+
+=over 4
+
+=item Win32
+
+=over 4
+
+=item *
+
+Previously, when compiling with a 64-bit Visual C++, every Perl XS module
+(including CPAN ones) and Perl aware C file would unconditionally have around a
+dozen warnings from F<hv_func.h>.  These warnings have been silenced.  GCC (all
+bitness) and 32-bit Visual C++ were not affected.
+
+=item *
+
+B<miniperl.exe> is now built with B<-fno-strict-aliasing>, allowing 64-bit
+builds to complete with GCC 4.8.
+L<[perl #123976]|https://rt.perl.org/Ticket/Display.html?id=123976>
+
+=back
+
+=back
+
+=head1 Selected Bug Fixes
+
+=over 4
+
+=item *
+
+Repeated global pattern matches in scalar context on large tainted strings were
+exponentially slow depending on the current match position in the string.
+L<[perl #123202]|https://rt.perl.org/Ticket/Display.html?id=123202>
+
+=item *
+
+The original visible value of L<C<$E<sol>>|perlvar/$E<sol>> is now preserved
+when it is set to an invalid value.  Previously if you set C<$/> to a reference
+to an array, for example, perl would produce a runtime error and not set PL_rs,
+but Perl code that checked C<$/> would see the array reference.
+L<[perl #123218]|https://rt.perl.org/Ticket/Display.html?id=123218>
+
+=item *
+
+Perl 5.14.0 introduced a bug whereby C<eval { LABEL: }> would crash.  This has
+been fixed.
+L<[perl #123652]|https://rt.perl.org/Ticket/Display.html?id=123652>
+
+=item *
+
+Extending an array cloned from a parent thread could result in "Modification of
+a read-only value attempted" errors when attempting to modify the new elements.
+L<[perl #124127]|https://rt.perl.org/Ticket/Display.html?id=124127>
+
+=item *
+
+Several cases of data used to store environment variable contents in core C
+code being potentially overwritten before being used have been fixed.
+L<[perl #123748]|https://rt.perl.org/Ticket/Display.html?id=123748>
+
+=item *
+
+UTF-8 variable names used in array indexes, unquoted UTF-8 HERE-document
+terminators and UTF-8 function names all now work correctly.
+L<[perl #124113]|https://rt.perl.org/Ticket/Display.html?id=124113>
+
+=item *
+
+A subtle bug introduced in Perl 5.20.2 involving UTF-8 in regular expressions
+and sometimes causing a crash has been fixed.  A new test script has been added
+to test this fix; see under L</Testing>.
+L<[perl #124109]|https://rt.perl.org/Ticket/Display.html?id=124109>
+
+=item *
+
+Some patterns starting with C</.*..../> matched against long strings have been
+slow since Perl 5.8, and some of the form C</.*..../i> have been slow since
+Perl 5.18.  They are now all fast again.
+L<[perl #123743]|https://rt.perl.org/Ticket/Display.html?id=123743>
+
+=item *
+
+Warning fatality is now ignored when rewinding the stack.  This prevents
+infinite recursion when the now fatal error also causes rewinding of the stack.
+L<[perl #123398]|https://rt.perl.org/Ticket/Display.html?id=123398>
+
+=item *
+
+C<setpgrp($nonzero)> (with one argument) was accidentally changed in Perl 5.16
+to mean C<setpgrp(0)>.  This has been fixed.
+
+=item *
+
+A crash with C<< %::=(); J->${\"::"} >> has been fixed.
+L<[perl #125541]|https://rt.perl.org/Ticket/Display.html?id=125541>
+
+=item *
+
+Regular expression possessive quantifier Perl 5.20 regression now fixed.
+C<qr/>I<PAT>C<{>I<min>,I<max>C<}+>C</> is supposed to behave identically to
+C<qr/(?E<gt>>I<PAT>C<{>I<min>,I<max>C<})/>.  Since Perl 5.20, this didn't work
+if I<min> and I<max> were equal.
+L<[perl #125825]|https://rt.perl.org/Ticket/Display.html?id=125825>
+
+=item *
+
+Code like C</$a[/> used to read the next line of input and treat it as though
+it came immediately after the opening bracket.  Some invalid code consequently
+would parse and run, but some code caused crashes, so this is now disallowed.
+L<[perl #123712]|https://rt.perl.org/Ticket/Display.html?id=123712>
+
+=back
+
+=head1 Acknowledgements
+
+Perl 5.20.3 represents approximately 7 months of development since Perl 5.20.2
+and contains approximately 3,200 lines of changes across 99 files from 26
+authors.
+
+Excluding auto-generated files, documentation and release tools, there were
+approximately 1,500 lines of changes to 43 .pm, .t, .c and .h files.
+
+Perl continues to flourish into its third decade thanks to a vibrant community
+of users and developers.  The following people are known to have contributed
+the improvements that became Perl 5.20.3:
+
+Alex Vandiver, Andy Dougherty, Aristotle Pagaltzis, Chris 'BinGOs' Williams,
+Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Mitchell,
+Father Chrysostomos, H.Merijn Brand, James E Keenan, James McCoy, Jarkko
+Hietaniemi, Karen Etheridge, Karl Williamson, kmx, Lajos Veres, Lukas Mai,
+Matthew Horsfall, Petr Písař, Randy Stauner, Ricardo Signes, Sawyer X, Steve
+Hay, Tony Cook, Yves Orton.
+
+The list above is almost certainly incomplete as it is automatically generated
+from version control history.  In particular, it does not include the names of
+the (very much appreciated) contributors who reported issues to the Perl bug
+tracker.
+
+Many of the changes included in this version originated in the CPAN modules
+included in Perl's core.  We're grateful to the entire CPAN community for
+helping Perl to flourish.
+
+For a more complete list of all of Perl's historical contributors, please see
+the F<AUTHORS> file in the Perl source distribution.
+
+=head1 Reporting Bugs
+
+If you find what you think is a bug, you might check the articles recently
+posted to the comp.lang.perl.misc newsgroup and the perl bug database at
+https://rt.perl.org/ .  There may also be information at
+http://www.perl.org/ , the Perl Home Page.
+
+If you believe you have an unreported bug, please run the L<perlbug> program
+included with your release.  Be sure to trim your bug down to a tiny but
+sufficient test case.  Your bug report, along with the output of C<perl -V>,
+will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
+
+If the bug you are reporting has security implications, which make it
+inappropriate to send to a publicly archived mailing list, then please send it
+to perl5-security-report@perl.org.  This points to a closed subscription
+unarchived mailing list, which includes all the core committers, who will be
+able to help assess the impact of issues, figure out a resolution, and help
+co-ordinate the release of patches to mitigate or fix the problem across all
+platforms on which Perl is supported.  Please only use this address for
+security issues in the Perl core, not for modules independently distributed on
+CPAN.
+
+=head1 SEE ALSO
+
+The F<Changes> file for an explanation of how to view exhaustive details on
+what changed.
+
+The F<INSTALL> file for how to build Perl.
+
+The F<README> file for general stuff.
+
+The F<Artistic> and F<Copying> files for copyright information.
+
+=cut
diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 3aa81ec2db..b96db871da 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -2,279 +2,383 @@
 
 =head1 NAME
 
-perldelta - what is new for perl v5.20.3
+[ this is a template for a new perldelta file.  Any text flagged as XXX needs
+to be processed before release. ]
+
+perldelta - what is new for perl v5.20.4
 
 =head1 DESCRIPTION
 
-This document describes differences between the 5.20.2 release and the 5.20.3
+This document describes differences between the 5.20.3 release and the 5.20.4
 release.
 
-If you are upgrading from an earlier release such as 5.20.1, first read
-L<perl5202delta>, which describes differences between 5.20.1 and 5.20.2.
+If you are upgrading from an earlier release such as 5.20.2, first read
+L<perl5203delta>, which describes differences between 5.20.2 and 5.20.3.
+
+=head1 Notice
+
+XXX Any important notices here
+
+=head1 Core Enhancements
+
+XXX New core language features go here.  Summarize user-visible core language
+enhancements.  Particularly prominent performance optimisations could go
+here, but most should go in the L</Performance Enhancements> section.
+
+[ List each enhancement as a =head2 entry ]
+
+=head1 Security
+
+XXX Any security-related notices go here.  In particular, any security
+vulnerabilities closed should be noted here rather than in the
+L</Selected Bug Fixes> section.
+
+[ List each security issue as a =head2 entry ]
 
 =head1 Incompatible Changes
 
-There are no changes intentionally incompatible with 5.20.2.  If any exist,
-they are bugs, and we request that you submit a report.  See L</Reporting Bugs>
-below.
+XXX For a release on a stable branch, this section aspires to be:
 
-=head1 Modules and Pragmata
+    There are no changes intentionally incompatible with 5.XXX.XXX
+    If any exist, they are bugs, and we request that you submit a
+    report.  See L</Reporting Bugs> below.
 
-=head2 Updated Modules and Pragmata
+[ List each incompatible change as a =head2 entry ]
+
+=head1 Deprecations
+
+XXX Any deprecated features, syntax, modules etc. should be listed here.
+
+=head2 Module removals
+
+XXX Remove this section if inapplicable.
+
+The following modules will be removed from the core distribution in a
+future release, and will at that time need to be installed from CPAN.
+Distributions on CPAN which require these modules will need to list them as
+prerequisites.
+
+The core versions of these modules will now issue C<"deprecated">-category
+warnings to alert you to this fact.  To silence these deprecation warnings,
+install the modules in question from CPAN.
+
+Note that these are (with rare exceptions) fine modules that you are encouraged
+to continue to use.  Their disinclusion from core primarily hinges on their
+necessity to bootstrapping a fully functional, CPAN-capable Perl installation,
+not usually on concerns over their design.
+
+=over
+
+=item XXX
+
+XXX Note that deprecated modules should be listed here even if they are listed
+as an updated module in the L</Modules and Pragmata> section.
+
+=back
+
+[ List each other deprecation as a =head2 entry ]
+
+=head1 Performance Enhancements
+
+XXX Changes which enhance performance without changing behaviour go here.
+There may well be none in a stable release.
+
+[ List each enhancement as a =item entry ]
 
 =over 4
 
 =item *
 
-L<Errno> has been upgraded from version 1.20_05 to 1.20_06.
+XXX
+
+=back
+
+=head1 Modules and Pragmata
+
+XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
+go here.  If Module::CoreList is updated, generate an initial draft of the
+following sections using F<Porting/corelist-perldelta.pl>.  A paragraph summary
+for important changes should then be added by hand.  In an ideal world,
+dual-life modules would have a F<Changes> file that could be cribbed.
 
-Add B<-P> to the pre-processor command-line on GCC 5.  GCC added extra line
-directives, breaking parsing of error code definitions.
-L<[perl #123784]|https://rt.perl.org/Ticket/Display.html?id=123784>
+[ Within each section, list entries as a =item entry ]
+
+=head2 New Modules and Pragmata
+
+=over 4
 
 =item *
 
-L<Module::CoreList> has been upgraded from version 5.20150214 to 5.20150822.
+XXX
 
-Updated to cover the latest releases of Perl.
+=back
+
+=head2 Updated Modules and Pragmata
+
+=over 4
 
 =item *
 
-L<perl5db.pl> has been upgraded from 1.44 to 1.44_01.
+L<XXX> has been upgraded from version A.xx to B.yy.
+
+=back
+
+=head2 Removed Modules and Pragmata
+
+=over 4
 
-The debugger would cause an assertion failure.
-L<[perl #124127]|https://rt.perl.org/Ticket/Display.html?id=124127>
+=item *
+
+XXX
 
 =back
 
 =head1 Documentation
 
+XXX Changes to files in F<pod/> go here.  Consider grouping entries by
+file and be sure to link to the appropriate page, e.g. L<perlfunc>.
+
+=head2 New Documentation
+
+XXX Changes which create B<new> files in F<pod/> go here.
+
+=head3 L<XXX>
+
+XXX Description of the purpose of the new file here
+
 =head2 Changes to Existing Documentation
 
-=head3 L<perlfunc>
+XXX Changes which significantly change existing files in F<pod/> go here.
+However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
+section.
+
+=head3 L<XXX>
 
 =over 4
 
 =item *
 
-Mention that L<C<study()>|perlfunc/study> is currently a no-op.
+XXX Description of the change here
 
 =back
 
-=head3 L<perlguts>
+=head1 Diagnostics
+
+The following additions or changes have been made to diagnostic output,
+including warnings and fatal error messages.  For the complete list of
+diagnostic messages, see L<perldiag>.
+
+XXX New or changed warnings emitted by the core's C<C> code go here.  Also
+include any changes in L<perldiag> that reconcile it to the C<C> code.
+
+=head2 New Diagnostics
+
+XXX Newly added diagnostic messages go under here, separated into New Errors
+and New Warnings
+
+=head3 New Errors
 
 =over 4
 
 =item *
 
-The OOK example has been updated to account for COW changes and a change in the
-storage of the offset.
+XXX L<message|perldiag/"message">
 
 =back
 
-=head3 L<perlhacktips>
+=head3 New Warnings
 
 =over 4
 
 =item *
 
-Documentation has been added illustrating the perils of assuming the contents
-of static memory pointed to by the return values of Perl wrappers for C library
-functions doesn't change.
+XXX L<message|perldiag/"message">
 
 =back
 
-=head3 L<perlpodspec>
+=head2 Changes to Existing Diagnostics
+
+XXX Changes (i.e. rewording) of diagnostic messages go here
 
 =over 4
 
 =item *
 
-The specification of the POD language is changing so that the default encoding
-of PODs that aren't in UTF-8 (unless otherwise indicated) is CP1252 instead of
-ISO-8859-1 (Latin1).
+XXX Describe change here
 
 =back
 
 =head1 Utility Changes
 
-=head2 L<h2ph>
+XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here.
+Most of these are built within the directories F<utils> and F<x2p>.
+
+[ List utility changes as a =head2 entry for each utility and =item
+entries for each change
+Use L<XXX> with program names to get proper documentation linking. ]
+
+=head2 L<XXX>
 
 =over 4
 
 =item *
 
-B<h2ph> now handles hexadecimal constants in the compiler's predefined macro
-definitions, as visible in C<$Config{cppsymbols}>.
-L<[perl #123784]|https://rt.perl.org/Ticket/Display.html?id=123784>
+XXX
 
 =back
 
-=head1 Testing
+=head1 Configuration and Compilation
+
+XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
+go here.  Any other changes to the Perl build process should be listed here.
+However, any platform-specific changes should be listed in the
+L</Platform Support> section, instead.
+
+[ List changes as a =item entry ].
 
 =over 4
 
 =item *
 
-F<t/perf/taint.t> has been added to see if optimisations with taint issues are
-keeping things fast.
+XXX
+
+=back
+
+=head1 Testing
+
+XXX Any significant changes to the testing of a freshly built perl should be
+listed here.  Changes which create B<new> files in F<t/> go here as do any
+large changes to the testing harness (e.g. when parallel testing was added).
+Changes to existing files in F<t/> aren't worth summarizing, although the bugs
+that they represent may be covered elsewhere.
+
+[ List each test improvement as a =item entry ]
+
+=over 4
 
 =item *
 
-F<t/porting/re_context.t> has been added to test that L<utf8> and its
-dependencies only use the subset of the C<$1..$n> capture vars that
-Perl_save_re_context() is hard-coded to localize, because that function has no
-efficient way of determining at runtime what vars to localize.
+XXX
 
 =back
 
 =head1 Platform Support
 
-=head2 Platform-Specific Notes
+XXX Any changes to platform support should be listed in the sections below.
 
-=over 4
+[ Within the sections, list each platform as a =item entry with specific
+changes as paragraphs below it. ]
 
-=item Win32
+=head2 New Platforms
 
-=over 4
-
-=item *
+XXX List any platforms that this version of perl compiles on, that previous
+versions did not.  These will either be enabled by new files in the F<hints/>
+directories, or new subdirectories and F<README> files at the top level of the
+source tree.
 
-Previously, when compiling with a 64-bit Visual C++, every Perl XS module
-(including CPAN ones) and Perl aware C file would unconditionally have around a
-dozen warnings from F<hv_func.h>.  These warnings have been silenced.  GCC (all
-bitness) and 32-bit Visual C++ were not affected.
+=over 4
 
-=item *
+=item XXX-some-platform
 
-B<miniperl.exe> is now built with B<-fno-strict-aliasing>, allowing 64-bit
-builds to complete with GCC 4.8.
-L<[perl #123976]|https://rt.perl.org/Ticket/Display.html?id=123976>
+XXX
 
 =back
 
-=back
+=head2 Discontinued Platforms
 
-=head1 Selected Bug Fixes
+XXX List any platforms that this version of perl no longer compiles on.
 
 =over 4
 
-=item *
+=item XXX-some-platform
 
-Repeated global pattern matches in scalar context on large tainted strings were
-exponentially slow depending on the current match position in the string.
-L<[perl #123202]|https://rt.perl.org/Ticket/Display.html?id=123202>
+XXX
 
-=item *
+=back
 
-The original visible value of L<C<$E<sol>>|perlvar/$E<sol>> is now preserved
-when it is set to an invalid value.  Previously if you set C<$/> to a reference
-to an array, for example, perl would produce a runtime error and not set PL_rs,
-but Perl code that checked C<$/> would see the array reference.
-L<[perl #123218]|https://rt.perl.org/Ticket/Display.html?id=123218>
+=head2 Platform-Specific Notes
 
-=item *
+XXX List any changes for specific platforms.  This could include configuration
+and compilation changes or changes in portability/compatibility.  However,
+changes within modules for platforms should generally be listed in the
+L</Modules and Pragmata> section.
 
-Perl 5.14.0 introduced a bug whereby C<eval { LABEL: }> would crash.  This has
-been fixed.
-L<[perl #123652]|https://rt.perl.org/Ticket/Display.html?id=123652>
+=over 4
 
-=item *
+=item XXX-some-platform
 
-Extending an array cloned from a parent thread could result in "Modification of
-a read-only value attempted" errors when attempting to modify the new elements.
-L<[perl #124127]|https://rt.perl.org/Ticket/Display.html?id=124127>
+XXX
 
-=item *
+=back
 
-Several cases of data used to store environment variable contents in core C
-code being potentially overwritten before being used have been fixed.
-L<[perl #123748]|https://rt.perl.org/Ticket/Display.html?id=123748>
+=head1 Internal Changes
 
-=item *
+XXX Changes which affect the interface available to C<XS> code go here.  Other
+significant internal changes for future core maintainers should be noted as
+well.
 
-UTF-8 variable names used in array indexes, unquoted UTF-8 HERE-document
-terminators and UTF-8 function names all now work correctly.
-L<[perl #124113]|https://rt.perl.org/Ticket/Display.html?id=124113>
+[ List each change as a =item entry ]
+
+=over 4
 
 =item *
 
-A subtle bug introduced in Perl 5.20.2 involving UTF-8 in regular expressions
-and sometimes causing a crash has been fixed.  A new test script has been added
-to test this fix; see under L</Testing>.
-L<[perl #124109]|https://rt.perl.org/Ticket/Display.html?id=124109>
+XXX
 
-=item *
+=back
 
-Some patterns starting with C</.*..../> matched against long strings have been
-slow since Perl 5.8, and some of the form C</.*..../i> have been slow since
-Perl 5.18.  They are now all fast again.
-L<[perl #123743]|https://rt.perl.org/Ticket/Display.html?id=123743>
+=head1 Selected Bug Fixes
 
-=item *
+XXX Important bug fixes in the core language are summarized here.  Bug fixes in
+files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>.
 
-Warning fatality is now ignored when rewinding the stack.  This prevents
-infinite recursion when the now fatal error also causes rewinding of the stack.
-L<[perl #123398]|https://rt.perl.org/Ticket/Display.html?id=123398>
+[ List each fix as a =item entry ]
+
+=over 4
 
 =item *
 
-C<setpgrp($nonzero)> (with one argument) was accidentally changed in Perl 5.16
-to mean C<setpgrp(0)>.  This has been fixed.
+XXX
 
-=item *
+=back
 
-A crash with C<< %::=(); J->${\"::"} >> has been fixed.
-L<[perl #125541]|https://rt.perl.org/Ticket/Display.html?id=125541>
+=head1 Known Problems
 
-=item *
+XXX Descriptions of platform agnostic bugs we know we can't fix go here.  Any
+tests that had to be C<TODO>ed for the release would be noted here.  Unfixed
+platform specific bugs also go here.
 
-Regular expression possessive quantifier Perl 5.20 regression now fixed.
-C<qr/>I<PAT>C<{>I<min>,I<max>C<}+>C</> is supposed to behave identically to
-C<qr/(?E<gt>>I<PAT>C<{>I<min>,I<max>C<})/>.  Since Perl 5.20, this didn't work
-if I<min> and I<max> were equal.
-L<[perl #125825]|https://rt.perl.org/Ticket/Display.html?id=125825>
+[ List each fix as a =item entry ]
+
+=over 4
 
 =item *
 
-Code like C</$a[/> used to read the next line of input and treat it as though
-it came immediately after the opening bracket.  Some invalid code consequently
-would parse and run, but some code caused crashes, so this is now disallowed.
-L<[perl #123712]|https://rt.perl.org/Ticket/Display.html?id=123712>
+XXX
 
 =back
 
-=head1 Acknowledgements
+=head1 Errata From Previous Releases
 
-Perl 5.20.3 represents approximately 7 months of development since Perl 5.20.2
-and contains approximately 3,200 lines of changes across 99 files from 26
-authors.
+=over 4
+
+=item *
 
-Excluding auto-generated files, documentation and release tools, there were
-approximately 1,500 lines of changes to 43 .pm, .t, .c and .h files.
+XXX Add anything here that we forgot to add, or were mistaken about, in
+the perldelta of a previous release.
 
-Perl continues to flourish into its third decade thanks to a vibrant community
-of users and developers.  The following people are known to have contributed
-the improvements that became Perl 5.20.3:
+=back
+
+=head1 Obituary
 
-Alex Vandiver, Andy Dougherty, Aristotle Pagaltzis, Chris 'BinGOs' Williams,
-Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Mitchell,
-Father Chrysostomos, H.Merijn Brand, James E Keenan, James McCoy, Jarkko
-Hietaniemi, Karen Etheridge, Karl Williamson, kmx, Lajos Veres, Lukas Mai,
-Matthew Horsfall, Petr Písař, Randy Stauner, Ricardo Signes, Sawyer X, Steve
-Hay, Tony Cook, Yves Orton.
+XXX If any significant core contributor has died, we've added a short obituary
+here.
 
-The list above is almost certainly incomplete as it is automatically generated
-from version control history.  In particular, it does not include the names of
-the (very much appreciated) contributors who reported issues to the Perl bug
-tracker.
+=head1 Acknowledgements
 
-Many of the changes included in this version originated in the CPAN modules
-included in Perl's core.  We're grateful to the entire CPAN community for
-helping Perl to flourish.
+XXX Generate this with:
 
-For a more complete list of all of Perl's historical contributors, please see
-the F<AUTHORS> file in the Perl source distribution.
+  perl Porting/acknowledgements.pl v5.20.3..HEAD
 
 =head1 Reporting Bugs
 
diff --git a/vms/descrip_mms.template b/vms/descrip_mms.template
index 992d4ac9fd..cd5fdd2830 100644
--- a/vms/descrip_mms.template
+++ b/vms/descrip_mms.template
@@ -319,7 +319,7 @@ x2p : [.x2p]$(DBG)a2p$(E) [.x2p]s2p.com [.x2p]find2perl.com
 extra.pods : miniperl
 	@ @extra_pods.com
 
-PERLDELTA_CURRENT = [.pod]perl5203delta.pod
+PERLDELTA_CURRENT = [.pod]perl5204delta.pod
 
 $(PERLDELTA_CURRENT) : [.pod]perldelta.pod
 	Copy/NoConfirm/Log $(MMS$SOURCE) $(PERLDELTA_CURRENT)
diff --git a/win32/Makefile b/win32/Makefile
index 2909403bd0..6a48a0a62e 100644
--- a/win32/Makefile
+++ b/win32/Makefile
@@ -1192,7 +1192,7 @@ utils: $(PERLEXE) $(X2P) ..\utils\Makefile
 	copy ..\README.tw       ..\pod\perltw.pod
 	copy ..\README.vos      ..\pod\perlvos.pod
 	copy ..\README.win32    ..\pod\perlwin32.pod
-	copy ..\pod\perldelta.pod ..\pod\perl5203delta.pod
+	copy ..\pod\perldelta.pod ..\pod\perl5204delta.pod
 	cd ..\win32
 	$(PERLEXE) $(PL2BAT) $(UTILS)
 	$(MINIPERL) -I..\lib ..\autodoc.pl ..
@@ -1290,7 +1290,7 @@ distclean: realclean
 	-if exist $(LIBDIR)\Win32API rmdir /s /q $(LIBDIR)\Win32API
 	-if exist $(LIBDIR)\XS rmdir /s /q $(LIBDIR)\XS
 	-cd $(PODDIR) && del /f *.html *.bat roffitall \
-	    perl5203delta.pod perlaix.pod perlamiga.pod perlandroid.pod \
+	    perl5204delta.pod perlaix.pod perlamiga.pod perlandroid.pod \
 	    perlapi.pod perlbs2000.pod perlce.pod perlcn.pod perlcygwin.pod \
 	    perldos.pod perlfreebsd.pod perlhaiku.pod perlhpux.pod \
 	    perlhurd.pod perlintern.pod perlirix.pod perljp.pod perlko.pod \
diff --git a/win32/makefile.mk b/win32/makefile.mk
index f7f6675573..b7de4d05d9 100644
--- a/win32/makefile.mk
+++ b/win32/makefile.mk
@@ -1392,7 +1392,7 @@ utils: $(PERLEXE) $(X2P) ..\utils\Makefile
 	copy ..\README.tw       ..\pod\perltw.pod
 	copy ..\README.vos      ..\pod\perlvos.pod
 	copy ..\README.win32    ..\pod\perlwin32.pod
-	copy ..\pod\perldelta.pod ..\pod\perl5203delta.pod
+	copy ..\pod\perldelta.pod ..\pod\perl5204delta.pod
 	$(PERLEXE) $(PL2BAT) $(UTILS)
 	$(MINIPERL) -I..\lib ..\autodoc.pl ..
 	$(MINIPERL) -I..\lib ..\pod\perlmodlib.PL -q ..
@@ -1489,7 +1489,7 @@ distclean: realclean
 	-if exist $(LIBDIR)\Win32API rmdir /s /q $(LIBDIR)\Win32API
 	-if exist $(LIBDIR)\XS rmdir /s /q $(LIBDIR)\XS
 	-cd $(PODDIR) && del /f *.html *.bat roffitall \
-	    perl5203delta.pod perlaix.pod perlamiga.pod perlandroid.pod \
+	    perl5204delta.pod perlaix.pod perlamiga.pod perlandroid.pod \
 	    perlapi.pod perlbs2000.pod perlce.pod perlcn.pod perlcygwin.pod \
 	    perldos.pod perlfreebsd.pod perlhaiku.pod perlhpux.pod \
 	    perlhurd.pod perlintern.pod perlirix.pod perljp.pod perlko.pod \
diff --git a/win32/pod.mak b/win32/pod.mak
index 67ebbf40d2..4ec1e4937d 100644
--- a/win32/pod.mak
+++ b/win32/pod.mak
@@ -40,6 +40,7 @@ POD = perl.pod	\
 	perl5201delta.pod	\
 	perl5202delta.pod	\
 	perl5203delta.pod	\
+	perl5204delta.pod	\
 	perl561delta.pod	\
 	perl56delta.pod	\
 	perl581delta.pod	\
@@ -174,6 +175,7 @@ MAN = perl.man	\
 	perl5201delta.man	\
 	perl5202delta.man	\
 	perl5203delta.man	\
+	perl5204delta.man	\
 	perl561delta.man	\
 	perl56delta.man	\
 	perl581delta.man	\
@@ -308,6 +310,7 @@ HTML = perl.html	\
 	perl5201delta.html	\
 	perl5202delta.html	\
 	perl5203delta.html	\
+	perl5204delta.html	\
 	perl561delta.html	\
 	perl56delta.html	\
 	perl581delta.html	\
@@ -442,6 +445,7 @@ TEX = perl.tex	\
 	perl5201delta.tex	\
 	perl5202delta.tex	\
 	perl5203delta.tex	\
+	perl5204delta.tex	\
 	perl561delta.tex	\
 	perl56delta.tex	\
 	perl581delta.tex	\