On the new Reefer series tanks (mfr since 2020), the sump door closer springs were moved to a new center stand support brace instead of the stand frame, and the overflow control knob and return plumbing was moved around in the sump--which also moved the chambers in the sump around. The stand material was also changed to a laminated marine plywood instead of particle board. They added adjustable foot pads to help level the stand as well. They went with a little bit thicker glass which added a thicker seam of glue along the display. The Reefer 425XXL only has the single return pump nozzle in the surface skim screen.
Somewhat related---The new Reefer-S series 850 and1000 have euro bracing at the top. No other Red Sea systems have that. Supposedly to aid in glass support, but it seems to be more of a cleaning headache than anything else.