We're nearing the release of the first Android P Developer Preview (judging by how much activity has died down in AOSP), but there's still a few tidbits here and there of possible upcoming features in the next major version of Android. We recently learned about possible native Iris scanner support, privacy tweaks such as blocking camera and microphone access from idle apps, and much more. Now, we're seeing another feature in the works: enhanced call blocking features.

A new set of commits has shown up in the AOSP gerrit from a Sony engineer. Sony engineers have recently been behind a ton of carrier related changes in Android, such as giving the ability for carriers to define the LTE signal bars, hide the signal strength from settings, and add a national roaming toggle in settings, so it's not too surprising to see another change from them. The change this time is a lot more user friendly, though, as the commits add new features to the default dialer app: the ability to block calls from unknown numbers, private numbers, pay phones, or any numbers not in your contact list.

Existing Call Blocking Feature on the Google Pixel 2 XL running Android 8.1 Oreo

Currently, you are only able to block calls on a per-number basis. The numbers that you block must be added manually, which means you basically can only block calls from unwanted numbers after-the-fact. With these new settings, however, you can restrict who is allowed to call you so you won't ever be bothered by unwanted phone calls.

Here are the strings for the text that will be displayed in the new blocked numbers setting in the dialer app.

        
<!-- The name of a feature available under the Call settings. -->
<string name="phone_settings_call_blocking_txt">Call Blocking</string>
<!-- Call type to be blocked. See the explanatory text "phone_settings_number_not_in_contact_summary_txt". -->
<string name="phone_settings_number_not_in_contact_txt">Numbers not in Contacts</string>
<!-- Explanatory text under the call type "phone_settings_number_not_in_contact_txt". -->
<string name="phone_settings_number_not_in_contact_summary_txt">Block numbers that are not listed in your Contacts</string>
<!-- Call type to be blocked. See the explanatory text "phone_settings_private_num_summary_txt". This is also called Anonymous or Withheld depending on region. -->
<string name="phone_settings_private_num_txt">Private</string>
<!-- Explanatory text under the call type "phone_settings_payphone_summary_txt". -->
<string name="phone_settings_private_num_summary_txt">Block callers that do not disclose their number</string>
<!-- Call type to be blocked. See the explanatory text "phone_settings_private_num_summary_txt". -->
<string name="phone_settings_payphone_txt">Pay phone</string>
<!-- Explanatory text under the call type "phone_settings_payphone_txt". -->
<string name="phone_settings_payphone_summary_txt">Block calls from pay phones</string>
<!-- Call type to be blocked. See the explanatory text "phone_settings_unknown_summary_txt". -->
<string name="phone_settings_unknown_txt">Unknown</string>
<!-- Explanatory text under the call type "phone_settings_unknown_txt". This occurs when no caller ID information unavailable (e.g., international calls, IP phones that operators cannot identify the caller) -->
<string name="phone_settings_unknown_summary_txt">Block calls from unidentified callers</string>
<!-- Notification. Make this translation consistent with "phone_settings_call_blocking_txt". -->
<string name="phone_strings_call_blocking_turned_off_notification_title_txt">Call Blocking</string>
<!-- Notification that appears when the feature Call Blocking has been disabled. -->
<string name="phone_strings_call_blocking_turned_off_notification_text_txt">Call Blocking disabled</string>
<!-- Title of the dialog "phone_strings_emergency_call_made_dialog_text_txt". -->
<string name="phone_strings_emergency_call_made_dialog_title_txt">Emergency call made</string>
<!-- Notification details that appear when the user taps the notification "phone_strings_call_blocking_turned_off_notification_text_txt". -->
<string name="phone_strings_emergency_call_made_dialog_call_blocking_text_txt">Call Blocking has been disabled to allow emergency responders to contact you.</string>
    

According to the strings, you can block phone numbers in the following contexts:

• The phone number is not in your contacts list
• The phone number is not disclosed by the caller (Private)
• The phone number is from a pay phone
• The phone number does not have any caller ID information (Unknown/Unidentified)

Call blocking is disabled if a user places an emergency call, which makes sense as it's imperative that someone in distress is able to have emergency responders reach back to them. Responding to a comment from a Googler, the Sony engineer mentions that it is an "operator requirement" for a persistent notification to be displayed telling the user that call blocking has been disabled after an emergency call, so there should be no confusion or panic from the user in these circumstances.

Finally, it appears that these new enhanced call blocking features will be available only if your carrier allows it, which is disappointing. We can imagine certain carriers trying to sell you these call blocking features as part of an "added value" package.

Ultimately, this would be a great change to Android. Although there are many free call blocking apps on the Play Store, you are basically trusting that the app isn't doing anything with your call history. With a built in feature, you wouldn't have to worry about that.

Now, keep in mind that this feature hasn't actually been merged in AOSP yet. That means it isn't confirmed to ship with Android P yet, but it's very likely that it will be. A Googler reviewing the patch states that they are "very much in favor of this change as a whole" so it will likely be merged soon. It may not show up in the first Android P Developer Preview, but as we've seen with the Android Oreo Developer Previews, it's still possible for new features to be added even if the initial preview drops before the commits are merged.