Developers' Eyes on the Changes of Apps: An Exploratory Study on App Changelogs

Release planning for mobile apps has only recently become an area of active research. As a result, little is known about the types of requirements that app developers pay the most attention to when releasing an app. This research uses the changelogs of apps to shed light on this. We report the results of an exploratory study in which we analyzed the requirements that dominate the changes of apps, according to a set of 3000 changelogs collected from 120 apps from three categories in the Apple App Store: Travel, Social networking, and Books. We analyzed the changelogs in terms of functional and non-functional requirements, from a developers' perspective. Our results suggest that developers' releases are by far more concerned with non-functional requirements than with functional requirements. We also found that usability and maintainability are the most frequently mentioned non-functional requirements (NFRs) in the changelogs. Surprisingly, reliability requirements formed only a fraction of the total number of NFRs addressed in all changelogs of apps in the three selected App Store categories.