Using 3.5.50 on an Earmen Angel DAC connected via USB-C on an M2 Macbook Pro, Audirvana will not change the bitrate to match my source (currently 24b 92k) unless I turn off integer mode (or exclusive mode). With integer mode on it shows 32bit 92k on the bottom right. With integer mode off (or Exclusive mode off) it shows 24bit 92k.
From the Audirvāna Online User Guide (Click the (i) in the upper-right corner of a settings pop-up window… In this case the DAC Input settings pop-up window)
Audirvāna optimizes and streamlines the audio data path to minimize the undesirable effects associated with synchronous audio stream processing. Thus, the only real-time operation is reduced to a simple broadcast of the data in integer mode - Integer Mode.
This mode provides a data stream in a native format to the DAC, thus optimizing the load on your computer’s processor.