My Arylic Amp v2.0 device (sold in 2020 as 'Up2stream WiFi and Bluetooth5.0 HiFi Stereo Class D digital multiroom audio amplifier board 2.0', version on pcb show v1.1) is the predecessor of the Up2Stream Amp v4.0, see https://cdn.shopify.com/s/files/1/0072/6899/1049/files/Up2Stream_AMP_Mono_Manual-EN.pdf.
It is using a TI3116 from Texas Instruments as an amplifier and a AP8064 from MV silicon as MCU. According to https://www.diyaudio.com/community/threads/wiimu-a31-module-in-combination-with-adau1401-1701-dsp.345544/post-6137759 the I2S output of the A31 module is 16-bit with a sample rate of 44.1kHz (CD quality).