In the recent Android Open Source Project, information has come out that Google could remove the Android Debug Bridge (ADB) backup and restore feature from the upcoming Android versions. ADB backup & restore is a utility tool and also a part of the Android SDK package which allows the users to backup and restore the full data of the Android device without any root access.
This has more in-built functions other than backup and restore. You can also save private data and install apps without root. But according to a commit in AOSP which is titled as "Add depreciation warning to ADB backup/restore." A warning message will be displayed on the screen whenever any user runs this tool in the latest version of the Android. This is a clear indication that Google might remove the ADB backup & restore option.
This news can be sad for those users whose Android phones are not rooted but when it comes to the rooted Android users then there is plenty of apps available to replace ADB backup and restore tool. Although there are apps which allow to back and restore without root, they are not as useful as the ADB tool.
Switching between phones from the same manufacturer company as most of their devices have their own backup & restore tool which makes the work quite easy and sophisticated. But switching phones from different OEM's can be a pain, and the ADB tool performs this task with ease.
The best alternative of ADB backup and restore tool is Titanium Backup if your phone is rooted. This is just a warning from Google, and this news has not been confirmed yet. And How long this feature will last is also still a mystery.