If we do not recommend and do not test direct upgrades from 3.x to 5.x, we have the opportunity to clean up a fair chunk of code by making `MessagingService.minimum_version=40`
As Cassandra versions 4.x and 5.0 are all on `MessagingService.current_version=40` this would mean lifting MessagingService.minimum_version would make it equal to the current_version. Today already we don't allow mixed-version streaming. The only argument I can see for keeping minimum_version=30 is for supporting non-streaming messages between 3.x and 5.0 nodes, which I can't find a basis for. An _example_ of the code that can be cleaned up is in the patch attached to the ticket: CASSANDRA-18314 – Lift MessagingService.minimum_version to 40 What do you think?
