I recently looked at a curriculum for a basic level course of a well known vendor. What struck my eye was that IPv4 basics, including classes, was pretty high on the list of topics. Then I found stuff like RIP version 1 in the list of topics an IPv6 almost at the end of the list of topics.

My calendar says it’s the End of 2025 so IPv6 should be at least as important as IPv4. IPv4 classes should only be viewed in a historical context, same as RIPv1.