Uploading new APK with old keystore

Question

Can I upload a brand new Android app to the Play Store to replace my old app using the same keystore?

When I first started learning to program I made an app, it's become quite outdated and I was a newbie when I made it so it's a little sloppy. I'd like to update it but I'd like to start from scratch. What if I built it using the same package name and the old apps keystore, will Google Play accept that?

Will it notify end users of an update?

Will it install on the device without any problems?

Answer 1

In addition same package name and the old apps keystore,Read :

http://android-developers.blogspot.com/2011/06/things-that-cannot-change.html

A subtle but important aspect of what constitutes a break in compatibility is the android:name attribute of your activity, service, and receiver components. This can be surprising because we think of android:name as pointing to the private code implementing our application, but it is also (in combination with the manifest package name) the official unique public name for that component, as represented by the ComponentName class.

Answer 2

If you retain package id and old signing certificate, then you can release completely new app and it would show up as upgrade to your old application in Google Play to everyone who installed your old app.