Given a 5.21 ACTIVITI with Oracle backend. It should be updated.
If I upgrade to 6.0 community, the upgrade will be successful, but the status of running processes cannot be queried, the server process is fault due to a bug. The activiti-admin application cannot start in the case of Oracle backend, it wants to re-create an existing table, which fails. After three retries, initialization failed and the application will not start.
In case of 1.11.1 and 2.3. enterprise versions the DB schema successfully updated, however, new tables are created with a similar task, so the activiti-app no longer manages users in the previous ACT_IDUSER table, but users in the USERS table. The situation is similar in the case of the other tables: looking at the tables with the ACT prefix, the processes and models can be found in them, but the web interface of the activiti-app does not show any of them.