Raspbian OS upgrade

I found the OS image for the Companion computer at ArduSub OS image. That image is based on debian Jessie, which is at least five years old and not the latest stable release.
Is there an ArduSub image based on debian 10 Buster, or even debian 9 Stretch?

In the absence of packaged image for the Companion, has the ROV2 Heavy been verified after upgrading from debian 8 Jessie to debian 9 Stretch?

I’d like to upgrade the OS on the companion because I want a newer version of Python 3 and the numpy and opencv-contrib-python packages.