How to install iOS 7 version of an iOS 8 app?

[iMore Question]

Hi everyone,
I am trying to install Sunrise Calendar app on my iphone 4, but when downloading it shows a message like "needs ios 8". Sunrise app was once for iOS 7 and you can't upgrade an iPhone 4 to iOS 8, how can I install an older version of the app that supports iOS 7? My iphone is 7.1.2 now.

 

[Romes Daizy]

try installing it with appcake or appaddict