Yes. Your app is automatically updated with your new content, as well as new colors and new design options.
The only things that would require new submissions are items related to the app itself:
- app icon,
- app startup image (splash screen),
- app name,
- app description,
- categories and keywords,
- and the mobile website url (in settings>domain), if you change it after your app is published.
If you add new features in your app after it has been published. Only these features would require to submit the app again if you don’t have added them before publishing:
- Audio & Radio features (you can add them after your app is published but it will not work in background when the app is closed)
- Scan Code
- AdMob for iOS (For Android you can add AdMob banners or interstitals after your app is published, but iOS will need new publication)
Republishing an app for any of the above reasons will result in a republication fee of $10 for Android and $25 for iOS. For both iOS and Android this will be $30. For this reason please be sure to make sure you have exactly what you want in your app before publishing. But, adding or changing content to these features after your app has been published doesn’t require to publish again.