iTunes Connect - Get active user installs by app version
The new version of iTunes Connect includes App Analytics section, which can—among other tricks—show you how many active devices* you've had within a time range. It's also possible to get statistics on how many sessions* (= app active for at least 2 seconds) you've had within a time range. Both parameters are groupable by app version.
App Analytics has its own section on iTunes Connect, next to Sales and Trends.
What App Analytics doesn't show is how many installations are idly sitting in user's springboard, like Play Dashboard does.
*) User must had opted-in to share data with developers. This is usually done on device activation, after major upgrades and at any time via settings.
iTunes Connect does not provide this information. Right now, you can only filter by territory, platform, App Store category, content type and transaction type. There is no way of getting the information how many users are using a particular version of the app since
iTunes Connect is not a tracking tool.
If you want to collect more information about your app, how, when, where and by what kind of audience your app is used you should integrate one of the Analytics