The evolving nature of knowledge forces the regular update of ontologies which leads to the publication of new versions. However, the link between the successive versions of ontological elements is never specified. Users have therefore to deal with several ontology versions in order to guarantee an optimal use in the underlying systems. To overcome this barrier, we propose in this paper a knowledge graph able to represent all the versions of concepts by preserving the structural properties of the ontology. We show the added value of our graph on the maintenance of semantic annotations.