I get the error - Cannot find serializer for value 'Untyped value - when I invoke after passing a custom object in variable

I get the error - Cannot find serializer for value 'Untyped value - when I invoke process instance after passing a custom object in variable.
The custom object from another library and I cannot make changes. Plus I need the object as-is back in the delegates.
Please suggest how to avoid serialization of such custom object variables.

With the current 7.9 alpha release, you can use transient variables which are not serialized, see https://docs.camunda.org/manual/latest/user-guide/process-engine/variables/#transient-variables. Other than that, you could probably use a ThreadLocal instead of a variable to pass the value. Just make sure to clear the reference in any case.

with 7.9 alpha2 release, I am trying to start process with transient variable which is not primitive and not implements Serializable.
I followed the instructions described in the manual (https://docs.camunda.org/manual/latest/user-guide/process-engine/variables/#transient-variables), however the engine insist to serialize it although it’s transient, hence process start failed with exception “Cannot find serializer”

Transient primitive variable works for me.