Most pleasant way to ask users to switch to a new package (remove actual app and install new one)

I have 5 apps adapted to different countries. I could in the last week make a all-in-one app including the 7 countries (in 5 apps). So I would like my users to all switch to the international version 开发者_如何转开发that is much easier for me to maintain.

What is the strategy I should adopt to offer users the most confortable user experience in switching to the new app ? I aim to get a 100 % transfer rate.. :)

Users will have to erase their actual app and install the new one.

Thanks in advance, Stéphane

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well the first thing that comes to my mind is: because you can actually redirect to your app in the market you can post an update with a dialog showing up at startup explaining why they should download the new app and have it redirect (on ok and on canceled and on every click basically) to the market to download your new app. this however will block the usage of your app if they don't install the new one so there might be people frowning upon this move..

also what you can do is actually remove the previous app after instalation of the new one and keep that transition smoother for the users.

Because android doesnt allow apps with the same package names, you cant really merge things into one app.

i am also curious to see what others might suggest.

Hope this helps. Don't forget to vote :D.