In 7.10 we introduce support for Java 9 and above.
The previously included module "JAXB" was marked as deprecated and with Java 11 it was removed completely from the JDK.
We decided to shade "JAXB" and include it directly in the camunda-spin-dataformat-all artifact.
During an update to 7.10, the users must make a decision to switch to camunda-spin-dataformat-xml-dom or use the JAXB annotation from the shaded package. Otherwise, they could face different issues with their applications and serialization/deserialization of variables.

We should document this in the upgrade guide:
https://docs.camunda.org/manual/7.10/update/minor/79-to-710/