Here is a list of major enhancements in MyBatis 3.4.2.

• New option 'returnInstanceForEmptyRow' to control the behavior when a query returns a row with all columuns being null. #800
• Support 'default methods' on mapper interfaces. #709
• When no type handler is registered to a class, a type handler registered to its superclass can be used. #859
• New attributes properties is added to @CacheNamespace. #841
• New attributes name is added to @CacheNamespaceRef. #842
• Support the mechanism for initializing a cache after set all properties. #816
• Allow users to set default value in placeholders. #852
• Auto-detecting type handlers newly added in version 1.0.2 of TypeHandlers-JSR310. #727 #878

Although it may be rare, the following changes could affect existing solutions.

• The default value of aggressiveLazyLoading is changed to false. #825
• Raise a exception when keyProperty is not found. #782

Follow this link to see the full list of changes.