# Is there use of $\pi/8$-DQPSK as shown in MATLAB's documentation?

I was reading MATLAB's documentation on dpskmod. They gave an example of an $$\pi/8$$-DQPSK. I felt that this is strange as I have seen $$\pi/4$$-DQSPK and $$\pi/8$$-D8PSK, but I have not seen $$\pi/8$$-DQPSK.

Attached is a screenshot of the documentation showing $$\pi/8$$-DQPSK with 16 clusters in the constellation:

My question is: Is $$\pi/8$$-DQPSK actually used in industry or is this just a demonstration of the flexibility of MATLAB's functions?