The Edut L'Yisrael (a text on sources for customs surrounding weddings and births in Judaism, published in Israel c. 1960) brings sources for the custom to learn and post the night before the brit, as well as make a festive meal.
The Edut L'Yisrael (a text on sources for wedding and birth customs in Judaism, published in Israel around 1960) includes sources for the practice of studying and posting a notice the night before the brit ceremony, as well as preparing a celebratory meal.