Hi,
We have been using the customSessionFactories property in the ProcessEngineConfiguration to inject our own implementations of GroupEntityManager and UserEntityManager. After the upgrade to Activiti 5.13, our implementations were not picked up and the default ones were used. It turned out that in 5.13, the implemnetations of UserEntityManagerFactory and GroupEntityManagerFactory session factories are now expected to return UserIdentityManager and GroupIdentityManager respectively in the implementation of "Class<?> getSessionType()". This is different from what we used to do in 5.12 and older where the sessionType used where UserEntityManager and GroupEntityManager.
I am not sure if this has been already documented somewhere but just thought this might be useful to share.
Hassan