Android Market requires you to version your app and provides a version code and version name for such purpose. Version code is an Integer value that represents the version of your application code, relative to other versions. Version Name is a String value that represents the release version of app and this is what shown to Market users.
For example, initial release of your app, you can assign Version Code of 1 and for version name, 1.0.
For your updates, you have to have a higher version code (e.g. 2) and a version name of like 2.0 or 1.1 or any other string. However, keeping them in sync is recommended.
AppToMarket automates this for you. Prior to discussing what needs to be done in AppToMarket, follow step 1
1. First goto your Market console, select the app you want to upgrade, then on subsequent page, select ‘APK Files’ tab. This will you show you current version that you have. Use this to find out what your next version should be. (see market.png)
2. AppToMarket automates this upgrade for you during app conversion (version.png) to see how to manipulate these data. During AppToMarket conversion, just bump-up the Version (version code). This automatically changes the Version Name, BUT, you can change that as needed.
3. Once done, back to your Market console (back to market.png) and click ‘Upload APK’.
Any questions, see AI / AppToMarket forum HERE