my $next_version_key = $ordered_list->[($i+1)]->[0] 
     if( $ordered_list->[($i+1)] );

##</code><code>##

my $next_version_key = $ordered_list->[($i+1)]->[0] || undef;

##</code><code>##

[] to @{ $ordered_list }

##</code><code>##

 
[
  undef,
  {}
]

##</code><code>##

[
  ${\$VAR1->[3][0]},
  {}
]

##</code><code>##

my $next_version_key = $ordered_list->[($i+1)]->[0] || 0;

##</code><code>##

my $next_version_key = $ordered_list->[($i+1)]->[0] 
     if( $ordered_list->[($i+1)] );