AT&T starts testing cross-carrier VoLTE calls
AT&T says that its VoLTE signal reaches 96% of its LTE coverage area. That works out to 295 million POPs. With 27 million of its active subscribers eligible to receive the carrier's VoLTE signal, AT&T is ahead of the competition in this department.
Looking back at 2015, AT&T mentioned some of the calling options it is now offering to subscribers. For example, iPhone users with iOS 9 can take advantage of Wi-Fi calling in areas where an AT&T signal is hard to come by. AT&T says that it plans to offer the feature to other operating services (read Android) in the future. The mobile operator started offering the service in October.
Number Sync allows you to send or receive calls and texts sent to your mobile number through other devices, even if your phone is miles away and turned off. The Samsung Gear S2 smartwatch will now support Number Sync. And Advanced Messaging, which works with the Samsung Galaxy S5 mini and Samsung Galaxy S6 Active, allows you to see when a sent text has been received by the recipient. You will also know when the text has been read, and when a reply is being typed up. It also increases the size of files that can be texted to 10MB.
source: AT&T via Engadget