MG90 USB MGOS 4.4.1 firmware file

Am trying to upgrade two MG90 routers, via USB, running MGOS 4.4.0 firmware to the most current version but need to upgrade to MGOS 4.4.1 first.

I have been unable to find the USB MGOS 4.4.1 firmware file.

Could you please inform me on how i can obtain the USB MGOS 4.4.1 firmware file.