[ List each enhancement as a =head2 entry ]
+=head2 Infinity and NaN (not-a-number) handling improved
+
+Floating point values are able to hold the special values infinity
+(also -infinity), and NaN (not-a-number). Now we more robustly recognize
+and propagate the value in computations, and on output normalize them
+to C<Inf> and C<NaN>.
+
+See also the L<POSIX> enhancements.
+
=head1 Security
XXX Any security-related notices go here. In particular, any security
[ List each incompatible change as a =head2 entry ]
+=head2 Changes to the C<*> prototype
+
+The C<*> character in a subroutine's prototype used to allow barewords
+to take precedence over most, but not all subroutines. It was never
+consistent and exhibited buggy behaviour.
+
+Now it has been changed, so subroutines always take precedence over
+barewords, which brings it into conformity with similarly prototyped
+built-in functions:
+
+ sub splat($) { ... }
+ sub foo { ... }
+ splat(foo); # now always splat(foo())
+ splat(bar); # still splat('bar') as before
+ close(foo); # close(foo())
+ close(bar); # close('bar')
+
=head1 Deprecations
XXX Any deprecated features, syntax, modules etc. should be listed here.
=item *
-XXX
+Subroutines with an empty prototype and bodies containing just C<undef> are
+now eligible for inlining. [perl #122728]
=back
=item *
+L<ExtUtils::ParseXS>: Documentation has been added to
+F<ExtUtils-ParseXS/lib/perlxs.pod> concerning handling of locales when writing
+XS code.
+
+=item *
+
L<File::Find> has been upgraded from version 1.27 to 1.28.
C<find()> and C<finddepth()> will now warn if passed inappropriate or
L<POSIX> has been upgraded from version 1.42 to 1.43.
+The C99 math functions and constants (for example acosh, round,
+M_E, M_PI) have been added.
+
=item *
L<Pod::Perldoc> has been upgraded from version 3.23 to 3.24.
XXX Description of the change here
+=item *
+
+L<perlsyn>: An ambiguity in the documentation of the Ellipsis statement has
+been corrected. [perl #122661]
+
=back
=head1 Diagnostics
It used to roduce a syntax error, but now compiles it correctly.
[perl #80368]
+=item *
+
+It has always been the intention for the C<-B> and C<-T> file test
+operators to treat UTF-8 encoded files as text.
+(L<perlfunc|perlfunc/-X FILEHANDLE> has been updated to say this.)
+Previously, it was possible for some files to be considered UTF-8 that
+actually weren't valid UTF-8. This is now fixed. The operators now
+work on EBCDIC platforms as well.
+
+=item *
+
+Under some conditions warning messages raised during regular expression
+pattern compilation were being output more than once. This has now been
+fixed.
+
+=item *
+
+A regression has been fixed that was introduced in v5.20.0 (fixed in
+v5.20.1 as well as here) in which a UTF-8 encoded regular expression
+pattern that contains a single ASCII lowercase letter does not match its
+uppercase counterpart. [perl #122655]
+
+=item *
+
+Constant folding could incorrectly suppress warnings if lexical warnings
+(C<use warnings> or C<no warnings>) were not in effect and C<$^W> were
+false at compile time and true at run time.
+
=back
=head1 Known Problems