This release uses a new Raft consensus version, with the move to Hashicorp Raft v1. As a result **the Raft system in 5.0 is not compatible with the 4.0 series**. To upgrade from an earlier version to this release you should backup your 4.0 leader node, and restore the database dump into a new 5.0 cluster.
The rqlite server also supports explicitly setting the node ID. While it's not required to set this, it's recommended for production clusters.