Yes, there are new versions of the hotend (v2 and v2.5 apparently). I’ve only had a v1 and v2 in my hands. See this thread: Opinion on two hotends?
I can confirm that there isn’t any problem of using the new ones in the old printhead. both work perfectly fine for me. Don’t know if the old versions still work in the new print head, but that’s most likely not a big issue as people with new printheads probably won’t end up buying the old versions. (unless some shop had a huge stock left over)
Personally, just based on the looks, I would assume they are interchangeable.