I sent William and Catherine an anniversary card much later than I had hoped to but it did get mailed before the anniversary. I mailed it on the 18th of April.
The reply arrived today My mailman has decided to quit paying attention when on duty and left my mail with the neighbor again (so not happy about this) and she was kind enough to bring it over this evening May 10, 2017. It features This photo of the couple on their hike in Bhutan, The photo was taking legendary royal photographer Arthur Edwards of The Sun
With a typical message on the back