c:\@Work\Perl\monks>perl -wMstrict -MData::Dumper -le
"my %fields = (
   version1 => { 1 => 'Ok' },
   );
 $fields{version_TWO} = $fields{version1};
 print Dumper \%fields;
 print $fields{version1}   {1};
 print $fields{version_TWO}{1};
 ;;
 $fields{version1}{1} = 'Oops...';
 ;;
 print $fields{version1}   {1};
 print $fields{version_TWO}{1};
"
$VAR1 = {
          'version_TWO' => {
                             '1' => 'Ok'
                           },
          'version1' => $VAR1->{'version_TWO'}
        };

Ok
Ok
Oops...
Oops...