Detect if an app was uninstalled

Question

Is there a way to get a system notification when an app has been uninstalled?

I would like to maintain a table of all clients\' info currently using my app. However

Answer 1

You could simply do it the other way round and maintain a table of users actively using your app. Just call a webservice at a point in the program that show it is active. If an app isn't used for a certain time mark it as inactive.