...
our $VERSION = '2021.0814';
...
... $offs = () = /\PM/g;
...

##</code><code>##

...
our $VERSION = '2023.0511';
...
... $offs = /^\pM/ + ( () = /\PM/g );
...

##</code><code>##

$ uname -a
CYGWIN_NT-10.0-19045 titan 3.4.7-1.x86_64 2023-06-16 14:04 UTC x86_64 Cygwin

##</code><code>##

$ perl -v | head -2 | tail -1
This is perl 5, version 30, subversion 0 (v5.30.0) built for cygwin-thread-multi

$ perl -MO=Deparse -e '$offs = () = /\PM/g;'
$offs = () = /\PM/g;
-e syntax OK

$ perl -MO=Deparse -e '$offs = /^\pM/ + ( () = /\PM/g );'
$offs = /^\pM/ + (() = /\PM/g);
-e syntax OK

$ perl -v | head -2 | tail -1
This is perl 5, version 38, subversion 0 (v5.38.0) built for cygwin-thread-multi

$ perl -MO=Deparse -e '$offs = () = /\PM/g;'
$offs = () = /\PM/g;
-e syntax OK

$ perl -MO=Deparse -e '$offs = /^\pM/ + ( () = /\PM/g );'
$offs = /^\pM/ + (() = /\PM/g);
-e syntax OK

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

use Unicode::UCD "charprop";

print "Perl version: $^V\n";

print "Example chars with Mark property:\n";
print "COMBINING GRAVE ACCENT U+0300:     ", charprop("U+0300", "Gc"), "\n";
print "COMBINING ENCLOSING KEYCAP U+20E3: ", charprop("U+20E3", "Gc"), "\n";

my $x = "a\N{COMBINING GRAVE ACCENT}b\N{COMBINING ENCLOSING KEYCAP}c";

while ($x =~ /\pM/g) {
    print "Char at position @{[pos($x)-1]} HAS Mark property.\n";
}

while ($x =~ /\PM/g) {
    print "Char at position @{[pos($x)-1]} NOT Mark property.\n";
}

##</code><code>##

Perl version: v5.30.0
Example chars with Mark property:
COMBINING GRAVE ACCENT U+0300:     Nonspacing_Mark
COMBINING ENCLOSING KEYCAP U+20E3: Enclosing_Mark
Char at position 1 HAS Mark property.
Char at position 3 HAS Mark property.
Char at position 0 NOT Mark property.
Char at position 2 NOT Mark property.
Char at position 4 NOT Mark property.

##</code><code>##

Perl version: v5.38.0
Example chars with Mark property:
COMBINING GRAVE ACCENT U+0300:     Nonspacing_Mark
COMBINING ENCLOSING KEYCAP U+20E3: Enclosing_Mark
Char at position 1 HAS Mark property.
Char at position 3 HAS Mark property.
Char at position 0 NOT Mark property.
Char at position 2 NOT Mark property.
Char at position 4 NOT Mark property.