We're now in process of migration from 3.2 to 4.2.c Alfresco Community version. So far we've done it in a copy of production environment to weed out possible bugs.
The most unpleasant bug is when session is unexpectedly destroyed. We've been so far unable to find out the cause, but it seems that session gets destroyed after certain Lucene queries are executed.
Session timeout in web.xml is set to 480. Ticket properties in repository.properties are unchanged.
Some other parameters we changed and might be of importance are:
Has anyone else had experience with this?