We are announcing our little one on Christmas to everyone but trying to figure out how to announce it to my in laws?

We are stationed in Korea and since we are what feels like a day ahead we don’t want to just post it and them see it on fb. I was thinking of mailing something but it takes a week to two to get to the states. Not sure if it maybe takes longer with Xmas since all the mail this time of year.

This is our third child and it’s a rainbow baby.

Any ideas?