XMILE: An XML based approach for incremental code mobility and update. The eXtensible Markup Language (XML) was originally defined to represent Web content, but it is increasingly used to define languages, such as XPL, that are used for coding executable algorithms, policies or scripts. XML-related standards, such as XPath and the Document Object Model, permit the flexible manipulation of fragments of XML code, which enables novel code migration and update paradigms. The XMILE approach that we describe in this paper exploits these mechanisms in order to achieve flexible and fine-grained code updates, even without stopping execution. We describe a Java-based prototype that implements XMILE and our experience in using XMILE in the domain of code updates on mobile devices.