Apple doubles the maximum size of an App Store app to 4GB
Apple still has a 100MB limit on apps delivered via a cellular connection. On Wi-Fi, the limit matches the new 4GB maximum. Allowing those using a Wi-Fi conection to install larger sized apps makes sense, and keeps down the cost of installing apps on an iOS flavored device. Apple iPhone and iPad users will also have to keep an eye out on their native storage limits, especially those sporting 16GB models.
Expanding the maximum size of an app submission means that developers can include "more media in your submission and provide a more complete, rich user experience upon installation," according to Apple.
source: Apple via CultofMac