There was a problem with our suggested method of forwarding all emails using filters - if the message had a blank Subject header then it would not be
forwarded. Rather than using a more complex workaround we have implemented an additional filter, 'Always'. It's identical to 'Advanced' with a matching text of 'true'.
NOTE: This filter doesn't look at the values of either the matching text or the 'Not' field (NOT Always is never, which is pointless!).
We recommend that if you're currently using '*' in the matching text field you switch the look in field to 'Always' to guarantee every message is forwarded.