App different package name but same signing key?

Question

My android app has same signing key but different package name does it give any impact on my existing app, I want to know once i publish it , it will install as an update or as a complete new app ?

Because i want to update my app!

Answer 1

No impact.

Package manager use package name to identify each apk.

Signing key are used only during update process for check is apk will be replaced by the apk from the same developer or not.

Edit (due to question was edited):

1. You can't update your application if new APK has different package name.
2. You can have two applications signed by the same key installed on the same device.

Answer 2

It is better to create a different signing key for new package name but you can add another application with same signing key. This will be treated as a new application.