Legacy Duet Guide for Intel and Apple Silicon Macs
Legacy Apogee Duet USB units (Duet 2 and Duet for iPad and Mac) are currently compatible with both Intel-powered and Apple Silicon (M1, M2, M3, etc.) macs.
For Apple Silicon Macs, this requires installing the Apogee Control 2 software for Duet which replaces the previous Apogee Maestro 2 app.
After installing, all settings will be adjusted in the Apogee Control 2 app.
The Duet 3 guide explains all settings which will be similar for Duet USB units.
Direct Monitoring in Apogee Control 2
Enable direct monitoring by changing the Main/Headphone output to Mixer. 
When set as Mixer, the inputs and software playback are routed through the low-latency Mixer in Apogee Control 2 > then directly to Duet's Outputs.
You can adjust the volume levels and settings in Mixer 1 for both the input sources and playback channels that are sending audio to the output.
Known changes with Apogee Control 2 compared to Maestro 2:
-No onscreen pop up indicators when adjusting volume and input gain
-Control 2 does not support Logic Device Control for adjusting input settings (48v, input types) from within Logic.
-Mac keyboard volume control not functional
-For Duet 2 units (serials start with DTAB... or B1..):
-OLED graphical GUI issues when adjusting the volume from the knob.
Does not affect audio output and input, all levels will be shown in the apogee Control 2 app.
For Intel Macs the previous Apogee Maestro 2 app can be installed and used.
Duet Firmware Versions:
You can check Duet's firmware when connected by opening System Information on your Mac. Under Hardware > USB > Select Duet and check what number this shows by Version.
The firmware versions are:
1.38 for Duet 2
3.05 for Duet for iPad and Mac
As long as this is correct no future update is needed.
If your Duet's firmware is outdated, you can update it using the Duet Firmware updater app included with the Apogee Maestro 2 installer. This process requires an Intel Mac, and we suggest performing the firmware update on macOS 10.15 Catalina or earlier for smooth operation.
All Apogee Duet USB drivers can be downloaded here under Legacy Product Installers:
The current software and firmware versions are shown here
AVID PRO TOOLS DUET
For the AVID Pro Tools Duet, this is a discontinued AVID product
The drivers we provide on our site will not work for AVID Duet models
This unit is only compatible with Intel Macs up to Mac OS 10.14.6 with the drivers AVID provides here
DUET FIREWIRE
For Duet Firewire, this model is compatible with Intel macs up to Mac OS 12 Monterey. Duet Firewire is not compatible with Apple Silicon Macs.
See this article
We recommend using Duet Firewire driver on Mac OS 11 Big Sur or lower for Duet to be detected in the Apogee Maestro 2 App.
The last updated Duet Firewire driver compatible with Mac OS 10.9 - Mac OS 11 can downloaded under Legacy Product Installers