[stsffap]

Yes, Restate supports registering different versions of your handler code. Restate requires that the code is still available for as long as there is an in-flight invocation of your handler for a given version. Breaking your handler/long-running process up into multiple steps can shorten this time tremendously. Then, one only needs to make sure that the handler/process state is forward-compatible. For example, using Protobuf for your handler/process state will make this fairly straight-forward.