[markdown]# Frequently Asked Questions
**Q. What do the analytics at the top of overview page mean?**
**A.** The analytics on the overview page can be described as follows:
*New Users:* New Users are calculated by examining how many devices have downloaded and opened your app at least once in the time period
*Addressable Users:* Addressable Devices are the number of devices which have downloaded your app and opted-in/accepted push notifications.
*Total Sessions:* Is the total number of session during the set time period. A session is in progress when a user opens the app and starts using it until they close it
*Unique Sessions:* Unique Sessions is calculated from the unique users who open the app at least one time during the set period of time.
*Mean Session Time:* Mean session time measures the average amount of times users spent browsing within your app during the se time period.
*Time Spent in App:* The total time users spent within in your app during the set time period.
**Q. What are the Minimum OS versions you support on iOS and Android?**
**A.** On iOS we support iOS 7 and up and on Android, Android 2.3 (Gingerbread) and up.
**Q: What am I seeing in the Todays Status window at the bottom of the analytics overview?**
**A.** You see the following four data points:
* Today’s new users
* Today’s addressable users
* Today’s total sessions
* Today’s pushes sent
Figures are calculated from midnight to the viewing time today. You can see this time range at the top of the page.
**Q: If I see an error message about invalid certificates when uploading certs or trying to send push notifications to iOS devices what does this mean**
**A** The certs uploaded for your app in your *Settings > App Certs/Keys* as your Apple push notification certificates are invalid. These certs can be invalid for a number of reasons:
* you could be using the incorrect type of file/cert
* you may have uploaded a cert for a different app
* a development cert could be in the place of the enterprise cert or vice a versa
* the certs could be out of date
If you encounter such an error you should consult the documentation on Setting up APNs Certificates in the [iOS integration documentation](../libs/ios_start.md/#setting-up-apns-certificates) and double check you have uploaded the correct certs.
**How can I check if I have users who have become inactive?**
In *Analytics > Users Engagement* select the By Last Activity tab and you can see users broken down by the time since the last opened the app.
**Q. How can I target users who have become inactive to bring them back into the app?**
**A.** Create segments based on *App last opened X days ago* and use them to target pushes at users who haven’t opened the app in 7 days, 14 days etc.