An empirical study on release notes patterns of popular apps in the Google Play Store

Release notes of a new mobile release provide valuable information for app users about the updated functionality of an app. Moreover, app developers can use the release notes to inform users about the resolution of a previously reported issue in user reviews. Prior work shows that release notes are an essential artifact for app developers to announce the emergency fixes and the newly adopted features. However, little is known about the common practices adapted by app developers in preparing their release notes. In this paper, we are interested in capturing the common practices as release notes patterns. First, we conduct an online survey with 102 respondents to investigate their views on mobile release notes. Our results show that most developers find release notes to be useful for notifying their user-base. Then, we study release notes patterns by analyzing 69,851 releases and 67.7 million user reviews of 2,232 top free-to-download apps in the Google Play Store over three years (from April 2016 until April 2019). We observe that app developers tend to write either long release notes (over 50 words) or short release notes (less than 7 words). We use the characteristics of release notes, such as the number of words, to identify six patterns of release notes in mobile apps. We manually investigate the release notes from each of the six patterns, and find 17 release drivers for the release notes. We also find that apps with longer release notes tend to have higher average user ratings. Furthermore, we observe that a shift from rarely updated patterns to frequently updated patterns tend to have higher average user ratings. Our work shows potential directions for developers to improve the release note mechanisms in app stores.