Hi @leech
No the Couchbase Server version isn’t relevant here. The problem is that the transactions library is compiled against a particular version of a Reactive library, which includes this Flux.retryWhen method. But your project appears to be pulling in a different, incompatible, version of the Reactive library, that does not include that method.
The transactions library uses version 3.3.9 of the Reactive library. You can use your project management tool to get the transitive dependencies and see which project is pulling in a different, incompatible Reactive library.
I will also file a ticket to remove the transactions library dependency on this Flux.retryWhen method, since it appears to have been removed.