I think the design of the current CZ-20 is the same as the old one.
However, the battery compartment of the CZ-20 has an inner wall and an outer door (which is removable). What I mean is that the battery compartment is waterproofed separately from the rest of the machine. Even if the battery compartment leaks, water can never enter the machine through the battery compartment due to the sealed inner wall. This might be a new feature, but since I've only owned the CZ-20 for two years, I have no old model to compare with. Ask someone with an older cz 20 if theirs has the same battery compartment like mine. Other than this feature, I think everything else is the same as the older cz-20.