The keystore is lost

A keystore is the app's signing key. When it is lost, you cannot install a new version over the old one of the same app.

• You can open a new package name with a new keystore. That is not a continuation of the old app.
• If the key is lost on Play, Google has a key reset. Acceptance is not guaranteed.
• Keep the key file and the password apart from the package.

If you remember the password but the file is gone, the password does not bring the file back.