Newsletter subscription defaults to "On"

I recently upgraded to zc 1.3.8 and I have just noticed that all new customers, since the upgrade, are subscribed to the newsletter. We do not use newsletters and I do not give new customers the option to subscribe to a newsletter.

I did a dummy sign up which also defaulted to the "subscribed" option.

The option in "admin > confuguration > customer details > Show Newsletter Checkbox" is set to '0' and always has been.

I'm not sure if this is a problem with 1.3.8 or if I have made an error in the upgrade process. Does anybody else have the same issue?

Customers are no longer automatically subscribed if I make the following change:

In /includes/modules/create_account.php.

Change line 28 from:

 $newsletter = (ACCOUNT_NEWSLETTER_STATUS == '1' ? false : true);
```to:
```php
 $newsletter = (ACCOUNT_NEWSLETTER_STATUS == '0' ? false : true);
```Should I make this change permanent or am I missing something?

The following line also works.

$newsletter = (ACCOUNT_NEWSLETTER_STATUS == '1' ? true : false);