What changed in the seat cushion between the first-generation LiberNovo Omni and the newer SE, Gen, and Pro?

The core foam formula is unchanged: it's still multi-density foam. Two things changed: thickness increased from 5cm to 6cm, and the construction moved from a two-piece foam-plus-support-plate design (with an air gap between them) to one-piece integrated molding, where the support plate is embedded directly in the foam. This makes the cushion more stable and consistent over years of use.