I don't know what to say. I followed the link in the email, found the differences about the addresses. The previous years there were all two addresses and this year there is only one. I sent by Canada post regular with sugnature and succeeded with the sigunature done. People had the experience in previous years that they didn't follow the exact what the guide tells you and the right forms and got rejected. One person I know used couriers address and 3 weeks passed, still no sign of whereabouts of the package. Also some people got in by using that address. And that Po box has no siganiture is wong. Why would somebody thinks the po box for CIC is the same size as your house mail box and nobody is attending to? So it was just a reminder that says the differences between this year and the previous years.
Anyway, let's move on. Whatever you do, hope for the best.