android signing problem - not able to auto update.

[Abbas Aniefa]

I have created a application and released it with out signing it. After that i have done auto updated my application few times.

After few months , now would like to give a another update. if i install my application in mobile , its not getting install, its installed only after i uninstalled the existing application from the mobile.

in console its showing , "Change in application signature"

I know i made a mistake by not signing the application with private key at first time. But please any tell me How my default debug key has changed now..

is there any way to solve the issue? or i should ask my users to uninstall the application.

Thanks.