https://github.com/arsduo/koala/issues/369#issuecomment-42682959

gistfile1.pl

#!/usr/bin/env perl
use strict;
use warnings;
use Facebook::OpenGraph;
use Data::Dumper;
 
{
    my $fb = Facebook::OpenGraph->new(+{
        app_id  => $ENV{OLD_APP_ID},
        secret  => $ENV{OLD_SECRET},
        version => 'v1.0',
    });
    $fb->set_access_token($fb->get_app_token->{access_token});
    warn Dumper $fb->get('zuck', +{fields => 'name'});
    # $VAR1 = {
    #           'id' => '4',
    #           'name' => 'Mark Zuckerberg'
    #         };
}

{
    my $fb = Facebook::OpenGraph->new(+{
        app_id  => $ENV{NEW_APP_ID},
        secret  => $ENV{NEW_SECRET},
        version => 'v1.0',
    });
    $fb->set_access_token($fb->get_app_token->{access_token});
    warn Dumper $fb->get('zuck', +{fields => 'name'});
    # 803:- OAuthException:(#803) Cannot query users by their username (zuck)
    # GET /v1.0/zuck?fields=name HTTP/1.1
    # Connection: keep-alive
    # User-Agent: Facebook::OpenGraph/1.21
    # Authorization: OAuth XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    # Content-Length: 0
    # Host: graph.facebook.com
    # 
}
 
__END__