Using what you give above, I have JSON.pm version 2.97001

I think that's pretty close to the latest? Also I just installed JSON::XS and it seems like it makes no difference.

EDIT : I take it back, I had screwed up the installation of JSON::XS. When I got it installed correctly, this :

my $data3;
$data3->{"num"} = "3";
my $addr = $data3->{"num"} + 7;
my $body3 = $json->encode($data3);
print $body3;
[download]

Does indeed print this :

{
   "num" : "3"
}
[download]

I'm guessing the difference is in the version of the JSON module?