Yes, you can use the newer tips on the older models and the older tips on the newer models.
For me the newer tips are even worse than the older ones. The old ones at least had enough of a flange to grip my ear canals, but these newer ones just come out too easily. They're little more than rubber washers. The problem for me is that they're too big and I can't insert them deeply enough, so they don't stay put.
Proper fit is very difficult to achieve with these, but once I do it's worth it.