There are several benefits of upgrading the the newest UIPath platform, but the most important one is how much it evolved since the 2016 version. There is a bunch of new, awesome features that could be taken advantage of.
Naturally, there are several considerations here and you can probably guess that they relate to the compatibility issues. I would say that the workflows that were designed to work with the other versions of the software will require some significant rework. You will need to judge how much of maintenance will need to be done and whether you could combine it with adapting the workflows to run with newest version of UiPath software.
I would suggest a trial to see how the project will behave when opened in the newest version in the new environment and go from there.