I was running into some issues when updating to 2.3.16 (worms!) from around 2.3.4.1 (2.3.14.1 also broke compat) in regards to implementing ParameterNameAware.
If you have a bean, "MyBean", with properties "id" and "name", when implementing acceptableParameterName, before one needed only return true for "myBeanInstance.id" and "myBeanInstance.name" - whereas now one needs those along with "myBeanInstance", "id", and "name" for the action to correctly populate the bean on an action. While I might have a funky configuration involving Spring, the only change I made to experience the break was updating the Struts2 libraries. I did not notice that documented or mentioned anywhere, so I thought I'd pass the information along in case it did need to be documented or was a bug.
