  Internet of Things (IoT) systems are bundles of networked sensors and
actuators that are deployed in an environment and act upon the sensory data
that they receive. These systems, especially consumer electronics, have two
main cooperating components: a device and a mobile app. The unique combination
of hardware and software in IoT systems presents challenges that are lesser
known to mainstream software developers. They might require innovative
solutions to support the development and integration of such systems. In this
paper, we analyze more than 90,000 reviews of ten IoT devices and their
corresponding apps and extract the issues that users encountered while using
these systems. Our results indicate that issues with connectivity, timing, and
updates are particularly prevalent in the reviews. Our results call for a new
software-hardware development framework to assist the development of reliable
IoT systems.
