This is the first episode this season where the whole gang are in the same scene together.
Sheldon reveals that he shaves once every eleven days.
Within the series, it is never revealed what happened to the rabbit Howard found in the hot tub in the last chapter.
Eight episodes have a "Previously on The Big Bang Theory" review of past events. The first being episode 3.1, The Electric Can Opener Fluctuation (2009), which summarises episode 2.23, The Monopolar Expedition (2009) and it is narrated by Kaley Cuoco. The other seven are episodes 4.16 The Cohabitation Formulation (2011), 5.1 The Skank Reflex Analysis (2011), 5.24, The Countdown Reflection (2012), 6.1 The Date Night Variable (2012), 8.1 The Locomotion Interruption (2014), 9.1 The Matrimonial Momentum (2015), and 9.16 The Positive Negative Reaction (2016).
This episode was taped on February 2, 2016.