if can do that migration , how are we gonna handle data from relational database .As we know that camunda 8.8 doesn’t handle relational database.Any idea on this ?
The knowledge base only covers migration from Camunda 7 to Camunda 8, not from JBPM, and regarding database handling, Camunda 8 currently uses Elasticsearch/OpenSearch as the secondary store while RDBMS support for history data is in development. I found the following relevant resources:
- Migration journey - general patterns
- Camunda 8 database architecture
- RDBMS support roadmap
- Migration podcast - general approach
Does this help? If not, can anyone from the community jump in? 
Hints: Use the Ask AI feature in Camunda’s documentation to chat with AI and get fast help. Report bugs and features in Camuda’s GitHub issue tracker. Trust the process. 
Camunda 8.9 will add support for RDBMS as an alternative to Elasticsearch: 8.9 Release notes | Camunda 8 Docs
I’m not aware of existing migration tools for jBPM. However, you can take a look at following resources: