I had uploaded my app to Google Play (back when it was called Android Market) some time ago.
Today I updated the app, but I had deleted the previous keystore and created a new one.
When uploading, it says the APK must be signed with the same certificates as the previous version:
You uploaded an APK that is signed with a different certificate to your previous APKs. You must use the same certificate.
Your existing APKs are signed with the certificate(s) with fingerprint(s):
[ SHA1: 89:2F:11:FE:CE:D6:CC:DF:65:E7:76:3E:DD:A7:96:4F:84:DD:BA:33 ]
and the certificate(s) used to sign the APK you uploaded have fingerprint(s):
[ SHA1: 20:26:F4:C1:DF:0F:2B:D9:46:03:FF:AB:07:B1:28:7B:9C:75:44:CC ]
But I don't have this certificate, and don't want to delete and re-publish the application, because it has active users.
What can I do to sign my app with new certificate?