Running mixed versions of Cassandra 3.x and 4.x is supported in the same cluster for the purpose of live upgrades, though certain features (such as repair) are not supported while in a mixed-version state.
All of 3.0, 3.x, 4.0, and 4.1 can coexist for the purpose of upgrades. 4.0 and 4.1 are also fully compatible within the same cluster from a protocol perspective. But I wouldn’t expect it to be desirable to remain in such a configuration for any longer than it takes to complete a rolling upgrade of all instances. If you’d intended to remain in a mixed-version state for an extended period, could you say more about what might motivate that? – Scott > On Aug 14, 2023, at 10:26 AM, Doug Whitfield via user > <user@cassandra.apache.org> wrote: > > Hi folks, > > I know it is impossible to run 3.x and 4.x nodes in the same cluster. Is it > possible to run 4.0 and 4.1 nodes together? Is it a good idea? > > Doug Whitfield > > This e-mail may contain information that is privileged or confidential. If > you are not the intended recipient, please delete the e-mail and any > attachments and notify us immediately. >
