Yep, this is correct, see my original response up above.
You wouldn’t be able to use the existing Image Sensors. You would want to replace those with the PowerG model if you want to maintain the still image camera function. The PG9934 is the replacement for the indoor Image Sensor.
This post discusses in general how to get started with an existing IQ Panel and what to upgrade to if you have an original 3G IQ Panel instead of the IQ Panel 2.