Ontologies are commonly used as a semantically rich knowledge base in systems that specialize in management of unstructured information. However, the knowledge that ontologies represent is not static, but evolves over time, thus requiring appropriate ontology management and evolution mechanisms. This paper presents Heraclitus II, a framework for ontology management and evolution in the context of information management systems. By addressing specific needs of such systems, Heraclitus II aims at providing an easily maintained and constantly updated knowledge base.