In these lines:

   $new_client_hash{$new_key} = $clients{$old_key};
   $new_client_hash{$old_key} = \$new_client_hash{$new_key};
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$new_client_hash{$new_key} is already a reference so you are storing a reference to a reference to a hash. $clients{$old_key} is also a reference to a hash. If you store $clients{$old_key} in the new hash with both keys, they should both reference the same hash and your code should work with either key. Use this instead.

   $new_client_hash{$new_key} = $new_client_hash{$old_key} = $clients{
+$old_key};
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---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';
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