Call recording is actually not a new thing for mobile phone users but it seems this will come with more features better than the traditional call recording we are already used to.

HOW IT WILL WORK
Some code has been added to AOSP(Android Open Source Project) by Google’s engineers references the existence of a “call recording tone” that would presumably be played once users press the corresponding button in order to start recording their conversation.
The tone itself is said to be of the 1,400Hz variety, meaning people of all ages should be able to hear it without any issues, with one of the commits referring to it revealing that it’s meant to be played every 15 seconds while the conversation is being recorded, presumably as to remind the person who didn’t initiate the recording that it’s still participating in one.
The question now is this? Can your phone receive OS update? Funny but interesting thing is many Android users are yet to get Android 8.0 update and now a new version is on the way.