Versioned updates now throw VersionMismatchException instead of ConcurrentModification exception. This allows for more targeted catches. For historical reasons, this new exception extends ConcurrentModification so that any existing catch clauses will continue to work. However, applications should be updated to catch the new exception. A future release will change the parent type of VersionMismatchException to RuntimeException instead. See this discussion for more details.

Kotlin Support

Kotlin classes have worked with Morphia for years now but certain Kotlin features have started to cause problems as folks have started trying to use them in their applications. To this end a new module has been introduced, morphia-kotlin, to specifically focus on these cases. Chances are good that you won’t need this module but in some cases this new module can help. See the reference guide for more details.


The API is now explicitly decorated with @NonNull and @Nullable annotations to indicate which parameters and return values support null references. Your IDE should give you in place hints when you run afoul of these annotations and guide you to properly handling null values.