Uploaded workflow definitions are stored in the database as serialized objects. Every time, you have made incompatible changes to your extension classes, which are used in already uploaded workflows, you need to convert these workflows. Use the workflow converter utility for this. In case of an update of the CoreMedia Workflow Server, the workflows have to be converted, too. Otherwise, object deserialization errors can occur (see Oracle JDK documentation for details).
![[Caution]](../common/images/caution.png) | Caution |
|---|---|
Changes at classes that are used in uploaded workflows should happen with great care and intensive testing. The classes must be compatible with the uploaded XML workflow definition. |
See Section 5.9, “Pitfalls of Implemented Classes” for more hints on this topic.
 |  |  |
 |