As with any transition, I think you should be prepared for some effort. Apple let iWork apps lay fallow for awhile, but over the last few years they've released newer versions, including iCloud-based versions. In my experience, all sort of things contribute to transition hiccups. Fonts, transitions, graphics formats, for example. You may want to consider creating a bootable 10.12 disk, try a few things, and see what lays ahead for you.
One question for you - can you download an updated version as part of your purchase history?