The Trumps weren't the most hospitable to the Bidens as January 20 approached: Melania Trump broke with tradition and never gave first lady Dr. Jill Biden Biden a tour of the residence.
And Donald Trump never congratulated Joe Biden on winning the election -- nor did he even attend Biden's inauguration.
But one tradition the former president continued is that of leaving a note for his successor.
Biden confirmed the existence of the letter, but he's not dishing on its contents.
"The president wrote a very generous letter," Biden told reporters in the Oval Office Wednesday afternoon. "Because it was private, I will not talk about it until I talk to him."