Mender is a free open source end-to-end over-the-air software update manager with a client-server architecture. Whether the need is to install the latest security patch, delight customers with new features, or fix bugs - every company must be able to deploy over-the-air (OTA) software updates to their fleet of devices. Mender supports two different methods for updating a connected device remotely: system updates and application updates. In a system update, the entire disk partition is updated and even if the update only entails a small change it will include all software and firmware on the device. System updates provide the benefit of a secure and robust updates at the cost of file size, bandwidth, speed and memory foot print. Targeted application-level updates, which can be just a few kilobytes in size (compared to potentially hundreds of megabytes for system-level updates), enables much lower bandwidth usage, faster updates, and more frequent deployments. Which type of update method to opt for depends on the user's requirements and update strategy.