In the future update Android OS will be able to hide the display of signal reception power. This feature was found in the source code of AOSP developers from the forum XDA Developers. It is about the signal reception of cellular communications. At the moment it is unclear for what purposes this will be done. Perhaps the operators themselves asked this to avoid a huge number of complaints about the quality of the connection: ostensibly, users do not understand how this indicator actually works.
If you are concerned, do not worry about it. This feature will not affect the Android API, which means it will be possible to install a third-party application to test the network. Currently, there are two ways for the user to check the signal strength of the network. The first is to look at the indicator in the status bar, and the second - to find the "Signal level" item in the SIM card settings.
Most likely, this feature will appear already in Android P. The new version of OS should show in the spring of 2018.
Based on AndroidAuthority
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Read in Russian: Операторы смогут прятать от вас мощность сигнала сети, но это не точно