This plugin allows you to check if an app is installed on the user's device. It requires an URI Scheme (e.g. twitter://) on iOS or a Package Name (e.g com.twitter.android) on Android.
Apple changed the canOpenURL method on iOS 9. Apps which are checking for URL Schemes have to declare these Schemes as it is submitted to Apple. The article Quick Take on iOS 9 URL Scheme Changes expains the changes in detail.
canOpenURL
Simply open your app's .plist (usually platforms/ios/<appname>/<appname>-Info.plist) with an editor and add the following code with your needed Schemes.
platforms/ios/<appname>/<appname>-Info.plist)
<key>LSApplicationQueriesSchemes</key> <array> <string>twitter</string> <string>whatsapp</string> </array>