We experienced a java.lang.NullPointerException error message when opening the edit form of a certain BO after upgrading from 8.3 Build 2623 to 8.4 Build 2705.
It turns out that the culprit was a plain text attribute using the Checkbox widget. The settings of the attribute was mostly standard. It had 13 choices in total. The only thing we had to do to fix the error was removing the attribute from the form and re-adding it again. We figured this out through the process of elimination. We have a more detailed log message from the server that we could share if it might be helpful to anyone.
