Not quite the same as NFS 3 and NFS 4, but we intentionally use NFS 3 much of the time today even though NFS 4 is old.
This may be good for a fork...but why hang on to NFSv3 instead of stepping up to NFSv4??
Because the work differently and having the overhead of NFSv4 often does not make sense.
Can you give more detail?
They are very different protocols with a lot of different features. NFSv3 is much lighter than NFSv4.