Marshalling in JBoss Cache is now versioned. All communications between caches contain a version short which allows JBoss Cache instances of different versions to communicate with each other. Up until JBoss Cache 1.4.0, all versions were able to communicate with each other anyway since they all used simple serialization of org.jgroups.MethodCall objects, provided they all used the same version of JGroups. This requirement (more a requirement of the JGroups messaging layer than JBoss Cache) still exists, even though with JBoss Cache 1.4.0, we've moved to a much more efficient and sophisticated marshalling mechanism.

JBoss Cache 1.4.0 and future releases of JBoss Cache will always be able to unmarshall data from previous versions of JBoss Cache. For JBoss Cache 1.4.0 and future releases to marshall data in a format that is compatible with older versions, however, you would have to start JBoss Cache with the following configuration attribute:

  
<!-- takes values such as 1.2.3, 1.2.4 and 1.3.0 -->
<attribute name="ReplicationVersion">1.2.4</attribute>