There are many apps on Google Play Store that have not updated since ages. The developer of the apps is not updating due to various reasons despite many updates available for Android. This may not work in Android P.
According to a report of Android Police, Android P can block apps that are built for Android 4.1 or lower from running on your phone. This shows that the users who all are using the old apps will not able to use the same app if they upgrade to the Android P. Android P is the latest platform by Google for the smartphones.
The latest Android P is said to be better than its predecessors but with this betterment there are some other features. The Android P is said to make your smartphone more safe from the vulnerabilities. There are some apps that may be functional on your phone. These apps may have security vulnerabilities or can exploit the user’s data from your smartphones. This vulnerability can be fixed by updating the apps but as the apps are not getting updated since a long time it is not possible to fix the problem. These apps which are meant for Android 4.1 or older platforms may not get optimized for your new modern smartphones handset. There may arise an issue in forms of UI, resolution and many other problems.
Google is not the only company to go for this update but also Apple has announced that developers should update their to 64-bit if they want to stay in iTunes App Store. Android P is in developer preview mode and the release of the same is said to be during later part of the year.