Preclude Downgrade of app from different sources

I have an app with version 1.1 in one market (say getjar), and the same app with version 1.2 in another market (say amazon) ... this is done for some deeply esoteric reasons :D ... Seriously though, odd versions are FREE, while even versions are PAID.

If the user has already installed ver开发者_运维百科. 1.2, is it possible (such as setting a flag!) to disallow the phone from installing a lower version of the app?

Thanks,

Rajath

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If I understand correctly, you want to stop someone who has installed the app from amazon, from installing the one for getjar in its place. If that is the case, then the easiest way is to use different certificates to sign the apks that you make available through getjar and amazon. if the two apks are signed differently than Android will not permit one to be installed over the other.

This will not someone from manually uninstalling the amazon app, and then installing the getjar one, though.