In v2.13, it allows users to change DAC Filters Type. However, it only support specific models now(TT39518F01-PRO,EPZ TP35 Pro).
Off Topic, I know...
I haven't seen the EPZ TP35-Pro anywhere (?). There is an EPZ TP35 (non-pro), but it uses a CT7601 bridge, so very unlikely to be Walk Play-enabled...
As for the TT39518F01-Pro TTGK module (CB5100 Bridge > dual CS43198), I literally received mine today!

Here it is alongside the FiiO KA15 (Space Touch SPV5048pro Bridge/MCU/DSP > dual CS43198 > dual SGM8262), and my new Shanling M0S (single CS43131. It's a DAP but compact enough to also be used as a "super-dongle"

):
Forgot to include the JM20 in the family picture...
The module has both 3.5 SE and 4.4 Bal heaphones ports.
The 3 buttons are: Vol+ (short or long press supported), Play/Pause & Previous/Next track (double/triple click), and Vol-. I have tested this very briefly.
The module can also be started in UAC 1.0 mode, instead of the default UAC 2.0 (not tested).
TTGK's 'TTGK Station' app reported a FW update, which I did (update was super-fast!). Then I downloaded the latest version of 'Walk Play' app: it is updated almost once a week, so it's hard to keep up.
All the feature reported in
@myy0222 above post are there: PEQ (8x PK filters), DAC digital filters, Class AB/H mode, and low/high gain setting. That last one, I'm not sure how it works, as there is also a high/low gain switch on the module itself.