Old style Sonix (pre 05 I believe)
Older new style (after 05)
It appears they all still have a mech trigger. There are ways to make the pull lighter and shorter, but having done it myself it's not really worth it. Yes, in answer to your question, there is an electronic frame upgrade available. You can get either an ESP frame (older frame) or a newer CAMD frame. Pretty sure you can find them in various forum BSTs or on ebay. Not sure if a rocking trigger will fit, or if there are any newer versions.