First a caution: I was working hard (according my standards in updating my Indian news app. And today was the D day. I tried publishing it. But market site told I should use the same keystore as my previous version. My computer is formatted recently and I have not taken the back up of that keystore file. Now there is nothing else I can do except for unpublishing it and publishing with a new package name. I will be losing all my downloads. So please keep your .keystore file and its password very very safely. As someone in stockoverflow suggested, send it to yourself in gmail.