Today the official guest list for Crown Princess Máxima's 40th birthday party has been realeased. The celebrations are going to start with a concert in Amsterdam.
Invited are the following Royals:
Crown Prince Philippe and Crown Princess Mathilde
Crown Prince Frederik and Crown Princess Mary
Surprisingly not coming are Victoria & Daniel, Letizia & Felipe and Mette-Marit (her husband Haakon is invited). It's not clear though whether they haven't been invited or just can't attend due to engagements.