Office applications such as OpenOffice and Microsoft Office are widely used to edit the majority of today's business documents: office documents. Usually, version control systems consider office documents as binary objects, thus severely hindering collaborative work. Since XML has become a de-facto standard for office applications, we focus on versioning office documents by structured XML version control approaches. This enables state-of-the-art version control for office documents.A basic prerequisite to XML version control is a diff algorithm, which detects structural changes between XML documents. In this paper, we evaluate state-of-the-art XML diff algorithms w.r.t. their suitability to OpenOffice XML documents and the future OASIS office document standard. It turns out that, due to the specific XML office format, a careful examination of the diff algorithm characteristics is necessary. Therefore, we identify important features for XML diff approaches to handle office documents. We have implemented a first OpenOffice versioning API that can be used in version control systems as a replacement for line-based or binary diffs, which are currently used.