I'd say the big ones are:

Perl 5.8
Decent Unicode
Decent threading
PerlIO layer
Perl 5.10
Smart match operator
Defined-or operator
given and when
state
say
Perl 5.12
Implicit strictures
each(@array), keys(@array), values(@array)
package Foo::Bar 1.23;
Postfix form of when
Yada-yada-yada operator
Perl 5.14
push $arrayref, @items, etc
package Foo::Bar 1.23 { ... }
s///r
Perl 5.16
__SUB__
fc

I've specifically ignored any new pragmata and core modules, as those are often also available on CPAN for older versions.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re: Summary of salient changes to Perl 5 between the major releases? by tobyink
in thread Summary of salient changes to Perl 5 between the major releases? by Anonymous Monk

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