Android Question How to publish an appli in 2020

If you lost your sign key, its better to republish the app with another package name.

Once you loose the original sign key, you can not "update" any of the apps that used that sign key.

The only thing you can do is create a new key and as mentioned above, re-release your apps using the new key (and deactivate the older versions based on the old key)

It is also suggested to use the same key for all your apps, otherwise things can get very confusing and there really is no benefit to using different keys.

To publish an app, you need to compile in release mode (obfuscated recommended) with your new signing key.

In the New way, you will sing with any of your Keys, and Google will re-sing your app with An internal sing for your account.