This case is upgrade between same major release, so it is easier than that across major releases. Upgrade advisor in MyAutoSupport may also helps. It gives you detailed upgrade steps. By the way, if you have no reason to use 8.1.4P4, better to use latest patch release.
Have you used the upgrade advisor on the NetApp autosupport page?
I would advise using the upgrade advisor. This will tell you step by step what needs to be considered and how to perfom the upgrade step by step from the version you are on to the target OS you are going to.