Pekko supports rolling updates between two consecutive patch versions unless an exception is mentioned on this page. For example updating from 1.0.0 to 1.0.1. Many times, it is also possible to skip several versions and exceptions to that are also described here.
It’s not supported to have a cluster with more than two different versions. Roll out the first update completely before starting next update.
Rolling update from classic remoting to Artery is not supported since the protocol is completely different. It will require a full cluster shutdown and new startup.