1) We have a gitops workflow that the corresponding image was generated with OSL 1.35.0.  With the DataIndex corresponding to OSL 1.35.0, it was possible to create workflow instances, and send the corresponding MultipleProcessInstanceDataEvent events with :
 
 

kogito.events.grouping = true
kogito.events.grouping.binary=true
kogito.events.grouping.compress=true

 
 
It worked also fine even by setting  kogito.events.grouping.compress=false and using only binary.
 
2) If we take the same workflow image (produced with the OSL 1.35.0 builder) but now, we deploy that workflow with the code for OSL 1.36.0 (i.e. main), and the corresponding Data Index (main) build , we have that same workflow, with the same configuration, now fails when we try to create a workflow instance.
 
When the Data Index (main code) tries to process the event produced by the workflow, we can see the errors in the attached file.
 
3) If we instead produce a new image, for the same workflow, but produced with the OSL 1.36.0 (i.e. the code in main), that workflow with the Data Index (main code) works fine to process the binary mode events.
 
Considering that we don't have killer changes in the images builder, and, as the workflow is configured with the same properties etc, and the only "big" change is the Quarkus version bump.
 
It looks like the ProcessInstance binary events produced with the code generated in Quarkus 3.8.6, are not compatible with the DataIndex code generated in Quarkus 3.15.3.1.
 
4) More Info: If we use the new image for the workflow (builder in main) and the Data Index (code in main), and we deploy the WF , etc, and DON'T use the binary MultipleProcessInstanceDataEvent, it works fine too.
 
Which confirms 3)