Also, note that your code needs to know its own encoding.

use strict;
use HTML::Entities;
{
    my $TestStr = 'ï';
    print encode_entities($TestStr), $/;
}
{
    use utf8;
    my $TestStr = 'ï';
    print encode_entities($TestStr), $/;
}

__END__
ï
ï
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