Providing an up-to-date view on dynamically changing data presents difficulties. While several different data-dissemination platforms address the problem, client mobility is still a major challenge. Volatile wireless connections and resource limitations void the attempt to apply the same mechanisms that work in fixed-wired networks. The Rebeca publish-subscribe middleware implementation introduces several concepts for accommodating client mobility in publish-subscribe systems. We present experimental results that show how intelligent filtering mechanisms can save network bandwidth inside the infrastructure and at mobile clients while preserving the accuracy of client notifications.