Yes, the camera always worked. I got my Volla phone abt. 2 months ago and flashed to 4.3.0.15 using UBports Installer. Later I updated to 4.4.0.58 using CLI as written above. Again later, as 4.4.0.64 was published, I updated in the same way because the GUI updater never saw any update, but CLI update did always work.
As said, camera always worked, but I didn’t test Advanced Camera because I read about it’s problems with v. 4.4, Sailjail and so on and I don’t know if they were solved yet in the mean time. So the above is regarding the Jolla Camera app, not the Advanced Camera.
If camera works in V. 4.3.0.15, maybe update in two steps, 4.3.0.15 → 4.4.0.58 → 4.4.0.64 works better, so I hope, and did so on my Volla.
edit: As I got the phone abt 2 months ago, there was Ubuntu Touch installed before I flashed to 4.3.0.15.