Netty 4.2 is out now. After a cursory test, upgrading to Netty 4.2 seems not to break anythings for Lettuce users. Upgrading to Nett 4.2 would also allow refining the io_uring arrangement as io_uring has been promoted to a proper module.

See also https://github.com/netty/netty/wiki/Netty-4.2-Migration-Guide for the migration guide.