The XML has undoubtedly become a standard for data representation and manipulation. But most of XML documents are still created without the respective description of their structure, i.e. an XML schema. Hence, in this paper we focus on the problem of automatic inferring of an XML schema for a given sample set of XML documents. Contrary to existing approaches we propose an algorithm that exploits additional input information – an obsolete XML schema. Consequently, we are able to exploit the information which was correct once and to infer the schema more efficiently.