This date supercedes Jo's statement in 2001 that Dumbledore was "about 150 years old" (Blue Nose Day) and fits better with the dates that appear in Book 7. Regarding his month of birth, Rita Skeeter writes that Dumbledore was “nearing” his 18th birthday when he left Hogwarts in June, but was still 17 when he met Grindelwald (DH18). Basically, at some point during Grindelwald’s stay at Godric’s Hollow Dumbledore turned 18, so the month of his birth appears to be July or August.
Is the "1996" date from Rowling's website a typo, or intentional? We're hoping that Rowling will let us know. Readers are asking why the Lexicon has not changed its official dates to 1996, and our answer has nothing to do with disrespect to Jo or the world she created. Our answer is that a 1996 date has dire implications for the oldest law Jo set for her Wizarding World.
What are the implications? Let's say Dumbledore truly died at some point in 1996. He appears alive to everyone at Hogwarts until the end of Book 6 (firmly 1996-97 according to Rowling), so he would have had to be revived well enough (without dark magic) that a withered hand and reduced energy were the only observable results. So, a 1996 death goes against Jo’s most immutable rule of all: Magic cannot raise the truly dead.
We know the consistency of underlying rules of her world is vital to Jo; she says so in interview after interview. But her most important rule is that death is final, and a death date of 1996 for Dumbledore would violate that law. When you weigh Jo's rules and the whole of Book 6 against the possibility of a simple numerical mistake, I think it makes more sense to believe that the 1996 is simply a typo that will be corrected some day. --Lisa