2017 saw the first year-over-year decrease in the amount of apps on Apple's built-in App Store on iOS.
According to a new report by app insight firm Appfigures, there are two primary factors that contributed to the decrease in mobile applications on Apple's online storefront. The first factor is the implementation of a requirement for app developers and publishers to ensure that apps submitted to the App Store are built for a 64-bit architecture, which is a requirement for apps to run on iOS devices running version 11 or later. The second factor is Apple's stricter enforcement of its review guidelines for app submissions to its digital storefront (as reported by outlets such as AppleInsider back in March of 2017).
Following these new guidelines and requirements, Apple then set its sights on apps designed explicitly to be clones of popular apps and spam apps that were generated from templates that served little purpose except for generating ad revenue for their developers. These factors contributed to a 29% decrease in apps released on the App Store in 2017 when compared to how many released in 2016, as well as a 5 percent decrease in the total amount of apps in the store from 2.2 million to 2.1 million.