Such a long Gap is not tested (like 1.11 master with 1.7 nodes). And usually each release has some action required things, for example alpha features that changes the on-disk format for some resources, or yaml fields, etc.
The safe advice is to install a new cluster and migrate your services there. Specially if you only have 2 workers.
But it really depends on what features you are using (like alpha features that might have changed or even don’t exist, etc.).
Looking at the action required things from each release, and going one release at a Time, one by one, might be okay too.