Hi Bill,
Documentation for this workflow is still up to date: "The update action does not incorporate schema changes to the map area. For schema changes, re-create the offline map area."
You might not necessarily always experience sync failures if there is a schema mismatch between the offline edits in the replica and the parent service (depends on the edits and the schema changes), but it is certainly best practice to keep the offline map areas up to date to avoid failures.