Beginning with Android 4.4, you should stop listening for the SMS_RECEIVED_ACTION broadcast, which you can do at runtime by checking the platform version then disabling your broadcast receiver for SMS_RECEIVED_ACTION with
PackageManager.setComponentEnabledSetting(). However, you can continue listening for that broadcast if your app needs only to read special SMS messages, such as to perform phone number verification. Note that—beginning with Android 4.4—any attempt by your app to abort the SMS_RECEIVED_ACTION broadcast will be ignored so all apps interested have the chance to receive it.
Tip: To distinguish the two SMS broadcasts, imagine that the SMS_RECEIVED_ACTION simply says "the system received an SMS," whereas the SMS_DELIVER_ACTION says "the system is delivering your app an SMS, because you're the default SMS app."