Version: Firmware 13.1.3 + DOS 2.2.4 Date: 2019-02-12

[IRSI]

My impression of firmware 13.1.3 – dos 2.2.4 (Audirvana - Air WiFi - Devialet) is a little more clarity and “see through”, in addition more “tightened up” in the bass. But unfortunately tonal colors and musicality are gone, no fun listening. Especially on classical music these characteristics are evident.
I tried “downgrading” to 13.0.0 – dos 2.2.2, and got the message that it was successful, but Air did not work after downgrading. So something must have been (permanently) changed during the installation of 13.1.3. Unfortunately I am not aware of any method to do a “clean install” of earlier firmware?

I noticed the same issue! The downgrade from 13.1.3 to 13.0.0 works but the DOS doesn't downgrade. It stays at 2.2.4!! So it looks like we can't go back to DOS 2.2.2. After downgrading I can't play with Roon. The player says that the device is in use!

Hi. I have tried, as an experiment, and successfully downgraded from 13.1.3/2.2.4 back to 12.3.0/2.2.2, then upgraded again from 12.3.0/2.2.2 to 13.1.3/2.2.4. Not sure you can do it with the same result. But if yes, you can move from 13.1.3/2.2.4 to 12.3.0/2.2.2 then to 13.0.0/2.2.2 IF it is what you wanted. 

https://devialetchat.com/Thread-Devialet-Expert-Firmware-Archive

FYI, I am using 440PRO CI.

I have just tried this, but it doesn't work for my Devialet 250 PRO!   It still remains DOS 2.2.4