Existing package by the same name with conflicting signature already installed

izam

My game which had been created with GS 10.1 since february 2013 cannot publish using the later versions after GS 10.1
When attempting to install adhoc version published using GS 10.2 and up, on my android device this message appeared: "Application not installed. An existing package by the same name with a conflicting signature is already installed."

I used the same keystore file to sign. I cannot understand what this mean by conflicting signature. The only way I can get this right is to use GS 10.1 all the time to publish for android. I am not able to use the latest GS versions.

I'm surprised no one has experienced this.
This issue still is not rectified in GS 10.4. What am I to do if I can no longer use GS 10.1?

izam